This reverts the changes made in

https://chromium-review.googlesource.com/c/v8/v8/+/1695465
https://chromium-review.googlesource.com/c/v8/v8/+/1776078

We originally moved this protector to the native context to avoid
cross-native-context pollution of protector state. Ideally,
invalidating a protector in one NC should not affect any other NC.

But as it turns out, having the protector on the NC causes more
problems than it solves since all affected callers now need to find
the correct native context to check. Sometimes (e.g. in CSA regexp
builtins) it is possible to blindly check the current NC, but the
reasoning behind this optimization is tricky to understand.
Sometimes, fetching the correct NC is not possible due to access
restrictions. These implementation complexities outweigh the (unknown)
potential performance benefits.

In the future we should attempt to move away from the protector
concept for these kinds of checks.

Bug: chromium:1069964,v8:9463
Change-Id: I2cbb2ec7266282165dae5e4a6c8bdbda520c50a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2157382Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67415}