- Debugger stepping assumes that the pc points to the instruction
  that should get executed next, so we need to increment it when
  we hit a stop or a bkpt instruction or else we'll end up in an
  infinite loop.
- The "break" and the "stop unstop" command write into code space, so
  they need to temporarily make code space writable or else they
  just crash. (Note that this doesn't work for embedded builtins.)

Bug: v8:10164
Change-Id: Id77f5e97892076a9fdf8de0230632e0ce979da43
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2026732
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66039}