contain the requested zone.

And now that we have a fallback at all, remove the special case that
allowed for testing absl::LocalTimeZone() under TZ=US/Pacific.

And we might as well update the existing embedded data while we're here.

This is modifying the test framework only.

PiperOrigin-RevId: 454896078
Change-Id: I3ec8391a5a51fe1e86a14f39d57ed6dac89d5905