Terminal: work-around missing/out-of-order modifiers events

... more aggressively than before:
* Only use modifiers().
* Before forwarding any relevant event to the active state, first check
  whether the modifiers have changed.

While the issues should really be fixed where they originate (app
server?), this hopefully fixes all situations where the hyperlink mode
gets stuck.
kernel tracing: implement fallback for meta data allocation

We the meta data area couldn't be allocated in any of the supported
(reattachable) places, just use a static allocation. The tracing feature
wouldn't be available at all in such a case.
vm_page_allocate_page_run(): fix debug output
MultiAddressSpaceLocker::AddAreaCacheAndLock(): race condition

* Add a VMArea* version of AddArea().
* AddAreaCacheAndLock(): Use the new AddArea() version. This not only
  saves the ID hash table lookup, but also fixes a race condition with
  delete_area(). delete_area() removes the area from the hash before
  removing it from its cache, so iterating through the cache's areas
  can turn up an area that no longer is in the hash. In that case we
  would fail immediately. The new AddArea() won't fail in this
  situation, though.

Fixes #9686: vm_copy_area() could fail for the "commpage" area. That's
an area all teams share, so any team terminating while another one was
fork()ing could trigger it.