Summary:
add the injest_error_severity to control if it is a retryable IO Error or a fatal or unrecoverable error. Use a flag to indicate, if fatal error comes, the flag is set and db is stopped (but not corrupted).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8479

Test Plan: run  ./db_stress --reopen=0 --read_fault_one_in=1000 --write_fault_one_in=5 --disable_wal=true --write_buffer_size=3000000 -writepercent=5 -readpercent=50 --injest_error_severity=2 --column_families=1, make check

Reviewed By: anand1976

Differential Revision: D29524271

Pulled By: zhichao-cao

fbshipit-source-id: 1aa9fb9b5655b0adba6f5ad12005ca8c074c795b