When running with the simulator, Assembler::debug() can record an inline
comment to be printed when the simulator encounters it. We need to make
sure pools are not emitted while the comment is recorded in the code
stream.

However the BlockPoolsScope was missing its margin argument to tell it
how much code we're going to generate, and could forget to emit pools
when it should have, causing crashes later on when a branch cannot jump
over the code comment.

Bug: v8:12637
Change-Id: I39e50f176d87c781c865b81fb9aca57d69c8c019
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3494544Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/main@{#79317}