Add script auto_sanity_test.sh to perform auto sanity test

Summary:
Add script auto_sanity_test.sh to perform auto sanity test

usage: auto_sanity_test.sh [new_commit] [old_commit]

Running without commit parameter will do the sanity test with the latest
and the latest 10 commit.

Test Plan: ./auto_sanity_test.sh

Reviewers: haobo, igor

Reviewed By: igor

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17397