Attempt to read a freed `WT_REF`

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

#  RUN PARAMETERS

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

auto_throttle=0

firstfit=1

# bitcnt not applicable to this run

bloom=1

bloom_bit_count=32

bloom_hash_count=8

bloom_oldest=0

cache=1

checkpoints=1

checksum=uncompressed

chunk_size=2

compaction=0

compression=zlib

data_extend=0

data_source=table

delete_pct=1

dictionary=0

file_type=row-store

hot_backups=0

huffman_key=0

huffman_value=0

insert_pct=25

internal_key_truncation=1

internal_page_max=10

isolation=snapshot

key_gap=15

key_max=37

key_min=30

leaf_page_max=15

logging=0

merge_max=14

merge_threads=2

mmap=1

ops=100000

prefix_compression=1

prefix_compression_min=8

repeat_data_pct=60

reverse=0

rows=100000

runs=100

split_pct=76

statistics=1

threads=9

value_max=3013

value_min=1

# wiredtiger_config not applicable to this run

write_pct=32

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

WT-3  0x0000000000446f54 in __wt_illegal_value (session=0x1755340, name=0x0) at ../src/support/err.c:497

WT-4  0x0000000000460b01 in __wt_page_in_func (session=0x1755340, ref=0x7f3f4c060230, flags=0, file=0x672db0 "../src/btree/row_srch.c", line=284) at ../src/btree/bt_page.c:110

WT-5  0x000000000048453c in __wt_page_swap_func (session=0x1755340, held=0x1783fb8, want=0x7f3f4c060230, flags=0, file=0x672db0 "../src/btree/row_srch.c", line=284)

    at ../src/include/btree.i:752

WT-6  0x00000000004851f0 in __wt_row_search (session=0x1755340, srch_key=0x7f3f1c007728, leaf=0x0, cbt=0x7f3f1c007660, insert=0) at ../src/btree/row_srch.c:284

WT-7  0x00000000004c1a18 in __cursor_row_search (session=0x1755340, cbt=0x7f3f1c007660, insert=0) at ../src/btree/bt_cursor.c:158

WT-8  0x00000000004c1c7f in __wt_btcur_search (cbt=0x7f3f1c007660) at ../src/btree/bt_cursor.c:230

WT-9  0x0000000000491265 in __curfile_search (cursor=0x7f3f1c007660) at ../src/cursor/cur_file.c:177

WT-10 0x00000000004107eb in read_row (cursor=0x7f3f1c007660, key=0x7f3f48df9e10, keyno=14773) at ../../../test/format/ops.c:527

(gdb) print *ref

$1 = {page = 0x7f3f4c0602a0, home = 0xabababababababab, ref_hint = 2880154539, state = 2880154539, addr = 0xabababababababab, key = {recno = 12370169555311111083,

    ikey = 0xabababababababab, pkey = 12370169555311111083}, page_del = 0xabababababababab}

(gdb) print base

$5 = 55

(gdb) print cmp

$6 = 1

(gdb) print *pindex

$7 = {entries = 660, index = 0x7f3f1c098620}

(gdb) print child

$8 = (WT_REF *) 0x7f3f4c060230

(gdb) print pindex->index[54]

$9 = (WT_REF *) 0x7f3f4c060230

(gdb) print *pindex->index[53]

$10 = {page = 0x7f3f4c10a1a0, home = 0xabababababababab, ref_hint = 2880154539, state = 2880154539, addr = 0xabababababababab, key = {recno = 12370169555311111083,

    ikey = 0xabababababababab, pkey = 12370169555311111083}, page_del = 0xabababababababab}

(gdb) print *pindex->index[54]

$11 = {page = 0x7f3f4c0602a0, home = 0xabababababababab, ref_hint = 2880154539, state = 2880154539, addr = 0xabababababababab, key = {recno = 12370169555311111083,

    ikey = 0xabababababababab, pkey = 12370169555311111083}, page_del = 0xabababababababab}

(gdb) print *pindex->index[55]

$12 = {page = 0x7f3f4c060220, home = 0xabababababababab, ref_hint = 2880154539, state = 2880154539, addr = 0xabababababababab, key = {recno = 12370169555311111083,

    ikey = 0xabababababababab, pkey = 12370169555311111083}, page_del = 0xabababababababab}