[llvm] [RISCV] Port Expand Pseudos to NewPM (PR #218078)

[Sam Elliott via llvm-commits]

lenary wrote:

I will probably follow this up with a rename to "Late Expand Pseudos" given we now have 3 expand pseudo passes, and also split each into its own file (2 share a file and a third has its own)

https://github.com/llvm/llvm-project/pull/218078