Summary:
When atomic flush stress test fails, we print internal keys within the range with mismatched key/values for all column families.
Test plan (on devserver)
Manually hack the code to randomly insert wrong data. Run the test.
```
$make clean && COMPILE_WITH_TSAN=1 make -j32 db_stress
$./db_stress -test_atomic_flush=true -ops_per_thread=10000
```
Check that proper error messages are printed, as follows:
```
2019/07/08-17:40:14 Starting verification
Verification failed
Latest Sequence Number: 190903
[default] 000000000000050B => 56290000525350515E5F5C5D5A5B5859
[3] 0000000000000533 => EE100000EAEBE8E9E6E7E4E5E2E3E0E1FEFFFCFDFAFBF8F9
Internal keys in CF 'default', [000000000000050B, 0000000000000533] (max 8)
key 000000000000050B seq 139920 type 1
key 0000000000000533 seq 0 type 1
Internal keys in CF '3', [000000000000050B, 0000000000000533] (max 8)
key 0000000000000533 seq 0 type 1
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5549
Differential Revision: D16158709
Pulled By: riversand963
fbshipit-source-id: f07fa87763f87b3bd908da03c956709c6456bcab
f786b4a5b4