[StatepointLowering] Move an assertion; NFCI

Instead of running an explicit loop over `gc.relocate` calls hanging off
of a `gc.statepoint`, assert the validity of the type of the value being
relocated in `visitRelocate`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263516 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed