core: Refresh frame script on registration

[nivkner]

fixes #11467 and fixes #19692

while running a goto on a frame would normally cause its frame-script to be counted as already executed,
a newly registered frame-script does not seem to count as such.

the None case of queued_script_frame is, as far as i can tell, redundant given that last_queued_script_frame already prevents the same script from running twice, so it was removed to allow for simpler "refresh" logic.

[nivkner]

to double-check the point about None (and for the fun of it),
I wrote a TLA+ specification to verify that the Option is in fact redundant here.

what i got was that it is redundant as of 64d6bbf, so long as run_frame_internal is called at least once before run_frame_scripts.

given that run_frame_scripts is called only during the frame script phase, while run_frame_scripts is called during the enter phase, it seems likely.

EDIT: the explanation is that the only place that sets queued_script_frame to None is the same one that sets last_queued_script_frame to the its current value, so they are the same (and thus the is_fresh check fails, where it would have failed from the let Some(..) = ... check)

[nivkner]

decided to remove changes to queued_script_frame, to hopefully make it easier to review.

[Molisson]

Reviewed carefully (test files ignored) and seemed simple for me.