Code cleanup: Remove std::move() around xvalue (NFC)

Code cleanup: Remove std::move() around xvalue (NFC)

Remove std::move() around xvalue so that copy elision is eligible.
In case that copy elision is not appliable, the c++ standard also
guarantees the move semantics on xvalue.  Thus, it is not necessary
to wrap Args with std::move.

This also silence a warning since r240345.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240355 91177308-0d34-0410-b5e6-96231b3b80d8