Bug Segmentation fault occurs because input Option compaction_style is not satinized

[SHTUSIST]

Expected behavior

When option compaction_style is set to 5 or bigger by the user, rocksdb should santinize user's input or just raise Status::InvalidArgument because there are only 4 compaction styles.

Actual behavior

However, DB could accept the options.compaction_style =5.

Rocksdb could run successfully for a while and will crash as "Segmentation fault (core dumped)" until it occurs compaction.

Also, set compaction_style to negative integer will trigger this bug as same reason.

Steps to reproduce the behavior

Just run db_bench like below:
./db_bench --benchmarks=fillrandom --compression_type=none --compaction_style=5 --num=5000000

After running a while, Segmentation fault (core dumped) occurs.

[SHTUSIST]

Bug found by fuzzing.
If allowed, I could submit a PR to fix this bug

[cbi42]

Hi @SHTUSIST, feel free to open a PR for this.