Fix some final gcc warnings:

  * Manually roll googletest to get the fix in:
    https://crrev.com/d5ad28dbe14fca51038fb8c7610f11602b98f682
  * Remove some anonymous namespaces in tests because the types in those
    anonymous namespaces ended up being visible in non-anonymous
    classes.
  * Fix a RVO breaking std::move.
  * Change some known-too-short strncpys into memcpys

Bug: chromium:1307180
Change-Id: I0f64512f77655f3740fc297bbb2087e6c039f7f3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3735122
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81436}