sbbs

As reported by Ragnarok and The Lizard Master, invoking a JS global
hot-key handler (e.g. hitting Ctrl-U or Ctrl-P with the privatemsg
or nodelist modules installed as handlers) would lead to the global
object being cleared/corrupted so other scripts would then fail to
run correctly (e.g. Error: can't open sbbsdefs.js: No such file or directory)

This probably explains the JS_GC/JS_ENDREQUEST change needed when
the hotkey-specific JS runtime/context/scope was introduced last year.
Should revisit that too.