[llvm-branch-commits] [CodeGen] Give NewPM SplitCriticalEdge default values (PR #217504)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/217504

To match the legacyPM version. This is needed for migrating
RegBankSelect without explicitly passing nullptr to these parameters,
which is not ideal given the LegacyPM version already sets them to
defaults.