Preserve Options File (#13074)

Preserve Options File (#13074)

Summary:
In https://github.com/facebook/rocksdb/issues/13025 , we made a change to load the latest options file in the remote worker instead of serializing the entire set of options.

That was done under assumption that OPTIONS file do not get purged often. While testing, we learned that this happens more often than we want it to be, so we want to prevent the OPTIONS file from getting purged anytime between when the remote compaction is scheduled and the option is loaded in the remote worker.

Like how we are protecting new SST files from getting purged using `min_pending_output`, we are doing the same by keeping track of `min_options_file_number`. Any OPTIONS file with number greater than `min_options_file_number` will be protected from getting purged. Just like `min_pending_output`, `min_options_file_number` gets bumped when the compaction is done. This is only applicable when `options.compaction_service` is set.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/13074

Test Plan:
```
./compaction_service_test --gtest_filter="*PreservedOptionsLocalCompaction*"
./compaction_service_test --gtest_filter="*PreservedOptionsRemoteCompaction*"
```

Reviewed By: anand1976

Differential Revision: D64433795

Pulled By: jaykorean

fbshipit-source-id: 0d902773f0909d9481dec40abf0b4c54ce5e86b2