Summary:
…r multiple times"

This reverts commit e80709a3.

lingbin PR https://github.com/facebook/rocksdb/pull/3635 is causing some performance regression for seekrandom workloads
I'm reverting the commit for now but feel free to submit new patches 😃

To reproduce the regression, you can run the following db_bench command
> ./db_bench --benchmarks=fillrandom,seekrandomwhilewriting --threads=1 --num=1000000 --reads=150000 --key_size=66 --value_size=1262 --statistics=0 --compression_ratio=0.5 --histogram=1 --seek_nexts=1 --stats_per_interval=1 --stats_interval_seconds=600 --max_background_flushes=4 --num_multi_db=1 --max_background_compactions=16 --seed=1522388277 -write_buffer_size=1048576 --level0_file_num_compaction_trigger=10000 --compression_type=none

write stats printed by db_bench:

Table | | | | | | | | | | |
 --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
revert commit | Percentiles: | P50: | 80.77  | P75: |102.94  |P99: | 1786.44 | P99.9: | 1892.39 |P99.99: 2645.10 |
keep commit | Percentiles: | P50: | 221.72 | P75: | 686.62 | P99: | 1842.57 | P99.9: | 1899.70|  P99.99: 2814.29|
Closes https://github.com/facebook/rocksdb/pull/3672

Differential Revision: D7463315

Pulled By: miasantreble

fbshipit-source-id: 8e779c87591127f2c3694b91a56d9b459011959d