[llvm] [opt][NewPM] Add isRequired to passes named *VerifierPass (PR #76517)

[Arthur Eubanks via llvm-commits]

aeubanks wrote:

I wonder if we should change the default to a pass being required, and have passes specify that they're optional. this would probably require more code than we currently have, but we can add a test that at least optimization passes in the default optimization pipelines are properly marked as optional

https://github.com/llvm/llvm-project/pull/76517