[llvm] [RISCV] Move RISCVVMV0Elimination past pre-ra scheduling (PR #132057)

[Philip Reames via llvm-commits]

preames wrote:

FYI, I started looking at this from the perspective of the test diffs.  They are unfortunately massive, and include both improvements and regressions, and a few oddities.  I need to convince myself of the a couple oddities I spotted, but I think we're going to need performance data to justify that this is actually net positive.  

https://github.com/llvm/llvm-project/pull/132057