Add gotoroomfast command

[Ratismal]

Changes:

This is a variation of gotoroom that applies the two-frame fix currently used by room transitions. Using this will cause any script box that the player is in after the gotoroomfast to be immediately executed, instead of waiting two frames.

An implication of this is that gotoroomfast on a script box that reloads the room will cause the an infinite loop that will freeze the game until the execution limit is hit. Any documentation of this command should warn about this behaviour.

Thank you to @NyakoFox for helping with the implementation of this command. Thank you @Daaaav @mothbeanie and @NyakoFox for reviewing the concept of this command before I made this PR (they all gave an OK!).

Demonstration:
https://github.com/user-attachments/assets/b7a2121c-1e91-4e37-8bf3-ba09b4628538

Legal Stuff:

By submitting this pull request, I confirm that...

• My changes may be used in a future commercial release of VVVVVV
• I will be credited in a CONTRIBUTORS file and the "GitHub Friends"
  section of the credits for all of said releases, but will NOT be compensated
  for these changes unless there is a prior written agreement

[Daaaav]

I approve!

(I just noticed the commit message doesn't have a blank line after the first line, which is kind of expected to be there in git. Not world-ending for this one commit imo, but something to keep in mind for next time.)