[Statepoint] Add helper functions for GCRelocate and GCResult

These functions isGCRelocate and isGCResult are
similar to isStatepoint(const Value*).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305847 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed