test: Give instrumentation based profiling tests their own directory

These tests are logically related, but they're spread about several
different CodeGen directories. Consolidate them in one place to make
them easier to manage.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@203541 91177308-0d34-0410-b5e6-96231b3b80d8