SCI: SQ4: Zero gravity chase lockup

[sluicebox]

When swimming in zero gravity in the mall, the game can lock up if the Sequel Police shoot while ego swims past the edge of the screen. This bug is in all versions.

This is a tricky bug to reproduce since it depends on timing and the random placement of the police's laser blast, but the end result is that ego gets stuck colliding with it and so the script that moves ego on and off the screen locks up.

Attached is a save game from the CD version that is locked up and can be used to test the solution. Enter into the debugger:

send blast.1 signal 0:4002

This will unlock the game and is what the script patch accomplishes.

[sluicebox]

​https://github.com/scummvm/scummvm/pull/1529

[Filippos Karapetis <bluegr@…>]

In 36b4926:

SCI: Fix SQ4 zero gravity blast lockup, bug #10912