Revert r357452 - 'SimplifyCFG SinkCommonCodeFromPredecessors: Also sink...

Revert r357452 - 'SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)'

This revision causes tests to fail under ASAN. Since the cause of the failures
is not clear (could be ASAN, could be a Clang bug, could be a bug in this
revision), the safest course of action seems to be to revert while investigating.

llvm-svn: 357667