Summary:
Summary : 1. Add two arguments --compression_level_from and --compression_level_to to check
	  the compression size with different compression level in the given range. Users must
          specify one compression type else it will error out. Both from and to levels must
	  also be specified together.
	  2. Display the time taken to compress each file with different compressions by default.

Test Plan : make -j64 check
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6634

Test Plan: make -j64 check

Reviewed By: anand1976

Differential Revision: D20810282

Pulled By: akankshamahajan15

fbshipit-source-id: ac9098d3c079a1fad098f6678dbedb4d888a791b