AI: improved performance and fixed crashes on use cases with too much target options like "deals 5 damage divided as you choose" (related to #11285):

* added DebugUtil.AI_ENABLE_DEBUG_MODE for better IDE's debugging AI code;
 * it's a target amount optimizations;
 * it's use a grouping of possible targets due same static and dynamic stats (name, abilities, rules, damage, etc);
 * instead of going through all possible combinations, AI uses only meaningful targets from particular groups;

Mage/src/main/java/mage/target/TargetImpl.java

@@ -446,13 +446,6 @@ public abstract class TargetImpl implements Target {
         return !targets.isEmpty();
     }
 
-    /**
-     * Returns all possible different target combinations
-     *
-     * @param source
-     * @param game
-     * @return
-     */
     @Override
     public List<? extends TargetImpl> getTargetOptions(Ability source, Game game) {
         List<TargetImpl> options = new ArrayList<>();