[SelectionDAG] Move matchUnaryPredicate/matchBinaryPredicate into SelectionDAGNodes.h

This allows us to improve vector constant matching in more DAG code (backends, TargetLowering etc.).

Differential Revision: https://reviews.llvm.org/D43466

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@325815 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed