Summary:
Pad block based table based on super block alignment
Pull Request resolved: https://github.com/facebook/rocksdb/pull/13909
Test Plan:
Unit Test
No impact on perf observed due to change in the inner loop of flush.
upstream/main branch 202.15 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 >> /tmp/x1 2>&1; grep fillseq /tmp/x1 | grep -Po "\d+\.\d+ MB/s" | grep -Po "\d+\.\d+" | awk '{sum+=$1} END {print sum/NR}'
```
After the change without super block alignment 203.44 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 >> /tmp/x1 2>&1
```
After the change with super block alignment 204.47 MB/s
```
for i in `seq 1 10`; do ./db_bench --benchmarks=fillseq -num=10000000 -compaction_style=2 -fifo_compaction_max_table_files_size_mb=1000 -fifo_compaction_allow_compaction=0 -disable_wal -write_buffer_size=12000000 -format_version=7 --super_block_alignment_size=131072 --super_block_alignment_max_padding_size=4096 >> /tmp/x1 2>&1;
```
Reviewed By: pdillinger
Differential Revision: D83068913
Pulled By: xingbowang
fbshipit-source-id: eecd65088ab3e9dbc7902aab8c2580f1bc8575df
742741b175