iAs listed in the summary D77846, we have 5 different categories of bugs we're
checking for in CallAndMessage. I think the documentation placed in the code
explains my thought process behind my decisions quite well.
A non-obvious change I had here is removing the entry for
CallAndMessageUnInitRefArg. In fact, I removed the CheckerNameRef typed field
back in D77845 (it was dead code), so that checker didn't really exist in any
meaningful way anyways.
Differential Revision: https://reviews.llvm.org/D77866