[llvm] [MachinePipeliner] Remove isLoopCarriedDep and use DDG (PR #174394)

[Ryotaro Kasuga via llvm-commits]

kasuga-fj wrote:

@aankit-ca Thanks for your check. I merged all the preceding PRs. Could you please take a look at this one?

https://github.com/llvm/llvm-project/pull/174394