cursor remove tries to return a key that doesn't exist

############################################

#  RUN PARAMETERS

############################################

abort=0

alter=0

auto_throttle=1

backups=0

bitcnt=4

bloom=1

bloom_bit_count=43

bloom_hash_count=16

bloom_oldest=0

cache=37

cache_minimum=20

checkpoints=off

checkpoint_log_size=21

checkpoint_wait=86

checksum=uncompressed

chunk_size=8

compaction=0

compression=none

data_extend=0

data_source=file

delete_pct=80

dictionary=0

direct_io=0

encryption=none

evict_max=3

file_type=row-store

firstfit=0

huffman_key=0

huffman_value=0

independent_thread_rng=1

in_memory=1

insert_pct=1

internal_key_truncation=1

internal_page_max=15

isolation=random

key_gap=10

key_max=32

key_min=29

leaf_page_max=9

leak_memory=0

logging=0

logging_archive=1

logging_compression=none

logging_file_max=12507

logging_prealloc=1

long_running_txn=0

lsm_worker_threads=3

merge_max=4

mmap=1

modify_pct=2

ops=100000

prefix_compression=1

prefix_compression_min=6

quiet=1

read_pct=2

rebalance=0

repeat_data_pct=68

reverse=0

rows=100000

runs=1

salvage=0

split_pct=54

statistics=0

statistics_server=0

threads=27

timer=360

transaction_timestamps=0

transaction-frequency=62

value_max=80

value_min=3

verify=0

wiredtiger_config=

write_pct=15

############################################

==40111==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60700015a790 at pc 0x000000869ff5 bp 0x7f6bb2778cc0 sp 0x7f6bb2778cb8

READ of size 8 at 0x60700015a790 thread T58

    #0 0x869ff4 in __wt_row_leaf_key /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/include/btree.i:1001:9

    #1 0x865177 in __key_return /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_ret.c:62:11

    #2 0x8649ff in __wt_key_return /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_ret.c:267:3

    #3 0xaf6da7 in __wt_btcur_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_cursor.c:1089:4

    #4 0x97dffa in __curfile_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/cursor/cur_file.c:398:2

    #5 0x52c2a3 in row_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/ops.c:1698:9

    #6 0x527196 in ops /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/ops.c:808:9

    #7 0x7f6bc7067dc4 in start_thread /usr/src/debug/glibc-2.17-c758a686/nptl/pthread_create.c:308

    #8 0x7f6bc624e76c in __clone (/lib64/libc.so.6+0xf776c)

0x60700015a790 is located 0 bytes to the right of 80-byte region [0x60700015a740,0x60700015a790)

allocated by thread T58 here:

    #0 0x4dfa6d in calloc /home/bostic/src/llvm40/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:74

    #1 0x6330b2 in __wt_calloc /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/os_common/os_alloc.c:52:11

    #2 0x836ee9 in __wt_page_alloc /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_page.c:63:2

    #3 0x81ae8c in __wt_btree_new_leaf_page /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_handle.c:694:3

    #4 0x84c94c in __page_read /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_read.c:370:3

    #5 0x84a10c in __wt_page_in_func /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_read.c:592:4

    #6 0x900827 in __wt_page_swap_func /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/include/btree.i:1512:8

    #7 0x8fc2e8 in __wt_row_search /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/row_srch.c:446:14

    #8 0xaf06a1 in __cursor_row_search /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_cursor.c:377:2

    #9 0xaf6435 in __wt_btcur_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/btree/bt_cursor.c:1015:3

    #10 0x97dffa in __curfile_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/cursor/cur_file.c:398:2

    #11 0x52c2a3 in row_remove /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/ops.c:1698:9

    #12 0x527196 in ops /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/ops.c:808:9

    #13 0x7f6bc7067dc4 in start_thread /usr/src/debug/glibc-2.17-c758a686/nptl/pthread_create.c:308

Thread T58 created by T0 here:

    #0 0x4373c1 in __interceptor_pthread_create /home/bostic/src/llvm40/projects/compiler-rt/lib/asan/asan_interceptors.cc:305

    #1 0x64d040 in __wt_thread_create /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/os_posix/os_thread.c:30:2

    #2 0x522a3b in wts_ops /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/ops.c:164:3

    #3 0x5334dd in main /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/test/format/../../../test/format/t.c:209:5

    #4 0x7f6bc6178b34 in __libc_start_main /usr/src/debug/glibc-2.17-c758a686/csu/../csu/libc-start.c:274

SUMMARY: AddressSanitizer: heap-buffer-overflow /mnt/data0/jenkins/workspace/wiredtiger-test-race-condition-stress-sanitizer/build_posix/../src/include/btree.i:1001:9 in __wt_row_leaf_key

Shadow bytes around the buggy address:

  0x0c0e800234a0: fa fa 00 00 00 00 00 00 00 00 00 07 fa fa fa fa

  0x0c0e800234b0: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa 00 00

  0x0c0e800234c0: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00

  0x0c0e800234d0: 00 00 00 00 00 00 fa fa fa fa 00 00 00 00 00 00

  0x0c0e800234e0: 00 00 06 fa fa fa fa fa 00 00 00 00 00 00 00 00

=>0x0c0e800234f0: 00 00[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa

  0x0c0e80023500: fa fa fa fa fd fd fd fd fd fd fd fd fd fd fa fa

  0x0c0e80023510: fa fa 00 00 00 00 00 00 00 00 00 00 fa fa fa fa

  0x0c0e80023520: fd fd fd fd fd fd fd fd fd fd fa fa fa fa 00 00

  0x0c0e80023530: 00 00 00 00 00 00 00 00 fa fa fa fa 00 00 00 00

  0x0c0e80023540: 00 00 00 00 00 00 fa fa fa fa 00 00 00 00 00 00

Shadow byte legend (one shadow byte represents 8 application bytes):

  Addressable:           00

  Partially addressable: 01 02 03 04 05 06 07 

  Heap left redzone:       fa

  Freed heap region:       fd

  Stack left redzone:      f1

  Stack mid redzone:       f2

  Stack right redzone:     f3

  Stack after return:      f5

  Stack use after scope:   f8

  Global redzone:          f9

  Global init order:       f6

  Poisoned by user:        f7

  Container overflow:      fc

  Array cookie:            ac

  Intra object redzone:    bb

  ASan internal:           fe

  Left alloca redzone:     ca

  Right alloca redzone:    cb

==40111==ABORTING