[llvm][NFC] Use move instead of copy

Summary: For functions that accept an rvalue reference type
parameter, use move to avoid copying the parameter.

These were found when implementing CppCoreGuideline F.18 in
clang-tidy.

Committed on behalf of ccotter (Chris Cotter)

Reviewers: Michael137 thieta

Differential Revision: https://reviews.llvm.org/D142825