Disable saving like the original game did

[JohnnyWalkerDesign]

In Indiana Jones and the Last Crusade the original game deliberately prevents you from saving during the three challenges. It is part of the gameplay and the original design of the game. Other games have moments when you can't save, too, and these are respected by ScummVM (see Cruise for a Corpse).

ScummVM, however, ignores this restriction for Last Crusade, allowing the user to take a snapshot at any moment. While this can be fun, it is also essentially breaking the intended gameplay experience.

It also creates bugs. For example, during the third trial the player must click on the other side of the chasm without much hesitation. If they delay Indy will fall.

With ScummVM the user can save after this time has passed, and then find themselves in a state where it's impossible for Indy to cross. (This happened to a friend of mine recently -- took forever for me to realise what had caused the problem.)

My request is to disable the saves just like the original game did. (And possibly put in an option to allow saving during the trials, for advanced players who wish to experiment.)

NOTE: I have been unable to test this with v2.2.0 yet. Apologies if my friend's version of ScummVM was older and this has been fixed already.