[PM] Add unittesting of the call graph update logic with complex

[PM] Add unittesting of the call graph update logic with complex
dependencies between analyses.

This uncovers even more issues with the proxies and the splitting apart
of SCCs which are fixed in this patch. I discovered this while trying to
add more rigorous testing for a change I'm making to the call graph
update invalidation logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307497 91177308-0d34-0410-b5e6-96231b3b80d8