Fix wrapping of toplevel gadget callins returning several parameters.

[saurtron]

Work done

• Fix wrapping of top level callins returning several parameters.
• Affected methods: GameSetup, AllowWeaponTarget, UnitPreDamaged, FeaturePreDamaged

Explanation

• It's a critical fix
• Looks like I introduced a bug at Add a mechanism so gadgetHandler reordering api can be used safely. #3907
• Sorry about that :P

Likely affected gadgets:

• GameSetup: none, still it can be affecting some engine calls since it will always return newReady nil, although afaics the engine won't accept the nil value so it shouldn't be affecting it.
• AllowWeaponTarget (affects returned priority): unit_aa_targeting_priority.
• UnitPreDamaged (affects impulse only): unit_combomb_full_damage, unit_dgun_behaviour, engine_hotfixes, unit_paralyze_damage_multiplier, map_lava, unit_paralyze_on_off, unit_collision_damage_behavior, unit_timeslow, unit_objectify, unit_evolution, unit_commando_watch, unit_shield_behaviour, unit_single_damage_fire, unit_lightning_splash_dmg, mo_preventcombomb, scav_spawner_defense, unit_no_land_damage.
• FeaturePreDamaged (affects impulse only): gfx_tree_feller.

[sprunk]

Looks good.

The multi return branch could probably be used for everything (i.e. the patch would be a 2-liner that changes res to res1, res2 where it is currently used) and then we would avoid the perf cost of handling the multiReturnTopCallins table in each GC cycle, I guess it's imperceptible either way though.

[saurtron]

Looks good.

The multi return branch could probably be used for everything (i.e. the patch would be a 2-liner that changes res to res1, res2 where it is currently used) and then we would avoid the perf cost of handling the multiReturnTopCallins table in each GC cycle, I guess it's imperceptible either way though.

ok did that now it will wrap two return parameters for everything