Revert "Remove -### from the -O20 test, it was failing the test (?)"

This reverts commit r194414.

Was breaking too many tests...



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194419 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Using an invalid -O falls back on -O3 instead of an error"

This reverts commit r194403.

Was breaking too many tests...



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194420 91177308-0d34-0410-b5e6-96231b3b80d8