Summary:
crash_test now only runs complicated options, multiple column families, prefix hash, frequently changing options, many compaction threads, etc. These options are good to cover new features but we loss coverage in most common use cases. Furthermore, by running only for multiple column families, we are not able to create LSM trees that are large enough to cover some stress cases.
Make half of crash_test runs the simply tests: single column family, default mem table, one compaction thread, no change options.

Test Plan: Run crash_test

Reviewers: rven, yhchiang, IslamAbdelRahman, kradhakrishnan

Reviewed By: kradhakrishnan

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D43461