Drop interference reassignment in favor of eviction.

The reassignment phase was able to move interference with a higher spill weight,
but it didn't happen very often and it was fairly expensive.

The existing interference eviction picks up the slack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128397 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed