Dynamic maybe-context/maybe-global lookup can fast-path in the case
where there are no context extensions in the parent contexts. Add a
trampoline builtin for maglev which performs this fast path.

This is similar to Sparkplug, which calls a similar builtin (except one
which loads context and FBV from Sparkplug frame slots), and unlike
TurboFan, which creates local control flow to inline this operation
fully. Maglev avoids creating local control flow, so the builtin
approach seems more fitting.

Bug: v8:7700
Change-Id: I2f63694d9c1f907f91b8b7b8982adc9f9ba106ca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3871210Reviewed-by: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82985}