Summary:
In https://github.com/facebook/rocksdb/issues/8268, the `db_stress` stdout began containing both the strings
"fail" and "error" (case-insensitive). The whitebox crash test
failed upon seeing either of those strings.
I checked that all other occurrences of "fail" and "error"
(case-insensitive) that `db_stress` produces are printed to `stderr`. So
this PR separates the handling of `db_stress`'s stdout and stderr, and
only fails when one those bad strings are found in stderr.
The downside of this PR is `db_stress`'s original interleaving of stdout/stderr is not preserved in `db_crashtest.py`'s output.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8272
Test Plan:
run it; see it succeeds for several runs until encountering a real error
```
$ python3 tools/db_crashtest.py whitebox --simple --random_kill_odd=8887 --max_key=1000000 --value_size_mult=33
...
db_stress: cache/clock_cache.cc:483: bool rocksdb::{anonymous}::ClockCacheShard::Unref(rocksdb::{anonymous}::CacheHandle*, bool, rocksdb::{anonymous}::CleanupContext*): Assertion `CountRefs(flags) > 0' failed.
TEST FAILED. Output has 'fail'!!!
```
Reviewed By: zhichao-cao
Differential Revision: D28239233
Pulled By: ajkr
fbshipit-source-id: 3b8602a0d570466a7e2c81bb9c49468f7716091e
b71b4597e7