PollyDependence: Simplify Read/Write/MayWrite before feeding them into ISL.

Contributed-by: Star Tan <tanmx_star@yeah.net>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@187981 91177308-0d34-0410-b5e6-96231b3b80d8
Create Memory Bandwidth.

Added a skeleton for creating the Memory Bandwidt pass.
Added some tests under the test directory for the Memory Bandwidth.
Working on adding a poly bench kernel to the test suite.
added  the latest poly bench to the test folder.
wirking on a python script to run the benchmark