[MinGW] Add the profiling library when necessary

Profiling still doesn't seem to work properly, but this at least
hooks up the library and eases completing whatever is missing.

Differential Revision: https://reviews.llvm.org/D58107

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@353917 91177308-0d34-0410-b5e6-96231b3b80d8