[llvm] [ARM] Add missing optimize compare candidates to isOptimizeCompareCandidates (PR #155886)

[Eli Friedman via llvm-commits]

https://github.com/efriedma-quic commented:

I'd like to see more test coverage here... the testing we have for optimizeCompareInstr is scattered all over, and it's not clear where to find it.  Don't know if we need a test for every single possible optimizable instruction, but some coverage would be nice.  Also, the name of the test isn't really intuitive.

https://github.com/llvm/llvm-project/pull/155886