Enable recycle_log_file_num option for point in time recovery (#12403)

Enable recycle_log_file_num option for point in time recovery (#12403)

Summary:
This option was previously disabled due to a bug in the recovery logic. The recovery code in `DBImpl::RecoverLogFiles` couldn't tell if an EoF reported by the log reader was really an EoF or a possible corruption that made a record look like an old log record. To fix this, the log reader now explicitly reports when it encounters what looks like an old record. The recovery code treats it as a possible corruption, and uses the next sequence number in the WAL to determine if it should continue replaying the WAL.

This PR also fixes a couple of bugs that log file recycling exposed in the backup and checkpoint path.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/12403

Test Plan:
1. Add new unit tests to verify behavior upon corruption
2. Re-enable disabled tests for verifying recycling behavior

Reviewed By: ajkr

Differential Revision: D54544824

Pulled By: anand1976

fbshipit-source-id: 12f5ce39bd6bc0d63b0bc6432dc4db510e0e802a