Race during checkpoint can cause a core dump

file:test00000.wt, WT_SESSION.checkpoint: src/reconcile/rec_write.c, 6061: size != 0 || cell_type == WT_CELL_ADDR_DEL

file:test00000.wt, WT_SESSION.checkpoint: aborting WiredTiger library

file:test00000.wt, WT_SESSION.checkpoint: process ID 23234: waiting for debugger...

(gdb) where

#0  0x00007fc5e378e3c3 in select () from /lib64/libc.so.6

#1  0x00000000004526bc in __wt_sleep (seconds=10, micro_seconds=0) at src/os_posix/os_sleep.c:23

#2  0x00000000004897dc in __wt_attach (session=0x10bcb40) at src/support/global.c:125

#3  0x000000000051e3e2 in __wt_abort (session=0x10bcb40) at src/os_common/os_abort.c:22

#4  0x000000000048933d in __wt_assert (session=0x10bcb40, error=0, file_name=0x561479 "src/reconcile/rec_write.c", line_number=6061, fmt=0x56126a "%s") at src/support/err.c:482

#5  0x000000000046ac42 in __rec_cell_build_addr (session=0x10bcb40, r=0x7fc0e43b9920, addr=0x0, size=0, cell_type=48, recno=0) at src/reconcile/rec_write.c:6061

#6  0x00000000004685ef in __rec_row_merge (session=0x10bcb40, r=0x7fc0e43b9920, page=0x7fc57d0b8b70) at src/reconcile/rec_write.c:4983

#7  0x0000000000468014 in __rec_row_int (session=0x10bcb40, r=0x7fc0e43b9920, page=0x7fc5aceef890) at src/reconcile/rec_write.c:4857

#8  0x000000000045f79a in __wt_reconcile (session=0x10bcb40, ref=0x7fc5c404c2a0, salvage=0x0, flags=1) at src/reconcile/rec_write.c:415

#9  0x00000000004d04d8 in __sync_file (session=0x10bcb40, syncop=WT_SYNC_CHECKPOINT) at src/btree/bt_sync.c:197

#10 0x00000000004d06c4 in __wt_cache_op (session=0x10bcb40, op=WT_SYNC_CHECKPOINT) at src/btree/bt_sync.c:277

#11 0x000000000049c170 in __checkpoint_tree (session=0x10bcb40, is_checkpoint=true, cfg=0x7fc5e117fe70) at src/txn/txn_ckpt.c:1390

#12 0x000000000049c432 in __checkpoint_tree_helper (session=0x10bcb40, cfg=0x7fc5e117fe70) at src/txn/txn_ckpt.c:1497

#13 0x0000000000498426 in __checkpoint_apply (session=0x10bcb40, cfg=0x7fc5e117fe70, op=0x49c3f3 <__checkpoint_tree_helper>) at src/txn/txn_ckpt.c:190

#14 0x000000000049a691 in __txn_checkpoint (session=0x10bcb40, cfg=0x7fc5e117fe70) at src/txn/txn_ckpt.c:731

#15 0x000000000049b2ae in __wt_txn_checkpoint (session=0x10bcb40, cfg=0x7fc5e117fe70) at src/txn/txn_ckpt.c:916

#16 0x0000000000483e25 in __session_checkpoint (wt_session=0x10bcb40, config=0x0) at src/session/session_api.c:1579

diff --git a/bench/wtperf/runners/500m-btree-50r50u.wtperf b/bench/wtperf/runners/500m-btree-50r50u.wtperf

index 06745bf..452ce43 100644

--- a/bench/wtperf/runners/500m-btree-50r50u.wtperf

+++ b/bench/wtperf/runners/500m-btree-50r50u.wtperf

@@ -7,7 +7,7 @@

 # checkpoints.  Collect wiredtiger stats for ftdc.

 conn_config="cache_size=16G,checkpoint=(wait=60,log_size=2GB),session_max=20000,log=(enabled),statistics=(fast),statistics_log=(wait=30,json),eviction=(threads_max=4)"

 create=false

-compression="snappy"

+compression="zlib"

 sess_config="isolation=snapshot"

 table_count=2

 key_sz=40

diff --git a/bench/wtperf/runners/500m-btree-populate.wtperf b/bench/wtperf/runners/500m-btree-populate.wtperf

index f9aed09..170ea0e 100644

--- a/bench/wtperf/runners/500m-btree-populate.wtperf

+++ b/bench/wtperf/runners/500m-btree-populate.wtperf

@@ -11,7 +11,7 @@

 # well and be small on disk.

 conn_config="cache_size=16G,checkpoint=(wait=60,log_size=2GB),session_max=20000,log=(enabled),statistics=(fast),statistics_log=(wait=30,json),eviction=(threads_max=4)"

 compact=true

-compression="snappy"

+compression="zlib"

 sess_config="isolation=snapshot"

 table_config="internal_page_max=16K,type=file,leaf_page_max=16K,memory_page_max=10M,split_pct=90"

 table_count=2