Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also...

Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"

Third time's the charm.

This was reverted in r363220 due to being suspected of an internal benchmark
regression and a test failure, none of which turned out to be caused by this.

llvm-svn: 363529