[NFC][clang] Fix Coverity static analyzer tool concerns about auto_causes_copy

    Reported by Coverity:

    AUTO_CAUSES_COPY
    Unnecessary object copies can affect performance

    Inside FrontendActions.cpp file,
    In clang::DumpModuleInfoAction::ExecuteAction(): Using the auto keyword without an & causes the copy of an object of type pair.

    Inside ComputeDependence.cpp file,
    In clang::computeDependence(clang::OverloadExpr *, bool, bool, bool): Using the auto keyword without an & causes the copy of an object of type TemplateArgumentLoc.

    Reviewed By: erichkeane, aaron.ballman

    Differential Revision: https://reviews.llvm.org/D147574