Let targets adjust operand latency of bundles

This reverts the AMDGPU DAG mutation implemented in D72487 and gives
a more general way of adjusting BUNDLE operand latency.

It also replaces FixBundleLatencyMutation with adjustSchedDependency
callback in the AMDGPU, fixing not only successor latencies but
predecessors' as well.

Differential Revision: https://reviews.llvm.org/D72535