R600: Add option to disable promote alloca

This can make writing some tests harder, so add a flag
to disable it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212893 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Run private-memory test with and without alloca promote

The unpromoted path still needs to be tested since we can't
always promote to using LDS.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212894 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Run more tests with promote alloca disabled.

Re-run tests changed in r211110 to test both paths.
Also fix broken check line.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212895 91177308-0d34-0410-b5e6-96231b3b80d8