Re-org the table tests

Summary:
We'll divide the table tests into 3 buckets, plain table test, block-based table test and general table feature test.
This diff does no real change and only does the rename and reorg.

Test Plan: run table_test

Reviewers: sdong, haobo, igor, dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15417