Reuse an existing diagnostic for tsan/msan needing -pie error.
Add a diagnosting for -fsanitize=memory conflicting with other sanitizers.
Extend tests.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169380 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed