Remove other unneccessary uses of -O3 in the test suite

The polly test suite is now -O3 clean.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@200205 91177308-0d34-0410-b5e6-96231b3b80d8
Do not test polybench with 'make check-polly'

Those test cases should be tested in the LLVM test suite. For Polly we should
extract regression tests for the individual passes.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@200206 91177308-0d34-0410-b5e6-96231b3b80d8