Upgrade third_party/googletest submodule to current main branch (#10393)

* Upgrade third_party/googletest submodule to current main branch

We can finally do this upgrade now that we have dropped our autotools
build. Googletest recommends living at head, so let's go straight to the
most recent commit on main. For some reason the googletest archive is
not present in the Bazel build mirror, so I removed that entry and just
left the GitHub download link in our WORKSPACE file.

Googletest now requires C++14, so I updated all the C++11 flags I could
find to C++14 instead. I added a .bazelrc file to add -std=c++14 for all
our Bazel builds.

* Delete the empty //src/google/protobuf:protobuf_test target

* Avoid building C++ unit tests in aarch64 jobs for Python and Ruby