[llvm] [MachinePipeliner] Make Recurrence MII More Accurate (PR #105475)

[Yuta Mukai via llvm-commits]

ytmukai wrote:

Can you add some tests that will show that RecMII is now being calculated correctly? It can be created by testing the debug output as follows:
https://github.com/llvm/llvm-project/blob/4a12722110abb2ccb98173c82a7d7b96a5c098e0/llvm/test/CodeGen/Hexagon/swp-resmii.ll#L5-L7

https://github.com/llvm/llvm-project/pull/105475