Summary:
MultiGet in block based table reader doesn't use BlockFetcher. As a result, the block_read_count and block_read_byte PerfContext counters were not being updated. This fixes that by updating them in MultiRead.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8676
Reviewed By: zhichao-cao
Differential Revision: D30428680
Pulled By: anand1976
fbshipit-source-id: 21846efe92588fc17123665dd06733693a40126d