Log Message:
googletest: update to 1.16.0.

C++ Language Support

    GoogleTest requires at least C++14 and follows Google's
    Foundational C++ Support Policy. See this table for a list of
    currently supported versions compilers, platforms, and build
    tools.
    The 1.16.x branch will be the last to support C++14. Future
    development will require at least C++17.

Notable Changes

    Bazel BUILD files now reference repositories by their canonical
    names from the Bazel Central Registry (cee1ba1). Users still
    using the old WORKSPACE system may need to use repo_mapping on
    repositories that still use the old names.
    Testsuite properties as are now exported as XML elements, not
    attributes (b4aae50).