[llvm] [AArch64][GISel] Separate legalize actions for G_FREEZE from G_IMPLICIT_DEF (PR #88469)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

Fundamentally G_FREEZE and G_IMPLICIT_DEF have the same property of being synthetic compiler operations that need to be legal for all register types. They really should have the same legalization rules. It may make sense to replace the current set of rules, but I think they should be moved together 

https://github.com/llvm/llvm-project/pull/88469