Disable file deletion before GetLiveFilesStorageInfo() in stress test

[hx235]

Context/Summary:
According to below API, we need to disable/enable file deletion when testing GetLiveFilesStorageInfo() in crash test.

...
If creating a live copy, use DisableFileDeletions() before and EnableFileDeletions() after to prevent deletions.
...
  virtual Status GetLiveFilesStorageInfo(
...

Otherwise we can run into failures like

Verification failed: VerifyGetLiveFilesStorageInfo failed: IO error: No such file or directory: while stat a file for size: /dev/shm/rocksdb_test/rocksdb_crashtest_blackbox/027550.log: No such file or directory

Test:
CI

[facebook-github-bot]

@hx235 has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[ajkr]

If creating a live copy, use DisableFileDeletions() before and EnableFileDeletions() after to prevent deletions.

VerifyGetLiveFilesStorageInfo() doesn't create a live copy. Should GetLiveFilesStorageInfo() call DisableFileDeletions() and EnableFileDeletions() internally?