[llvm] [SelectionDAG] Add support to filter SelectionDAG dumps during ISel by function names (PR #72696)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi approved this pull request.

I think this patch is good once the rather minor nits and documentation have been addressed.

I'd double check w/ @topperc before landing, though, since he had some questions on the overall direction.

https://github.com/llvm/llvm-project/pull/72696