[clang-tools-extra] Clean up strange uses of getAnalysisIfAvailable (PR #65729)

[Björn Pettersson via cfe-commits]

https://github.com/bjope commented:

I guess I don't know how pull requests and reviewing works in github. I actually added 3 comments on this patch a several days (or weeks) ago. But turns out that they were "pending" because I had only "started review" and not found the place to "submit review".

So sorry for some late comments here. Since this has been pushed already, then I guess you may ignore them. 

https://github.com/llvm/llvm-project/pull/65729