[wasm] Check correctness of thread-local write protection

We make an undocumented assumption in {CodeSpaceWriteScope} that a
single thread will only work on one module at a time. If this is
violated, the thread-local {code_space_write_nesting_level_} would
prevent the second module from being switched to writable.

This CL adds a second thread local (in debug only) to check that if
there is already a {CodeSpaceWriteScope} open that it contains the same
{NativeModule} as any nested scope.

R=jkummerow@chromium.org

Change-Id: I43fa886d9d0fdf0e1846137dc411745fcca471fa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3074477


Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76134}