MachineScheduler: Remove ineffective heuristic; NFC

Currently all nodes get added to the NextSU list when they are released,
so any candidate must be in that list, making the heuristic ineffective.
Remove it for now, we can add it back later in a working fashion if
necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282200 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed