Silencing some MSVC warnings about not all control paths returning a value when they actually do.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@194156 91177308-0d34-0410-b5e6-96231b3b80d8
Thread safety analysis: minor bugfix to smart pointer handling, and expanded
test case.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@194157 91177308-0d34-0410-b5e6-96231b3b80d8