Merge branch 'master' into 'master'

Fix NPE in CostPartWithList (will need further rework / generalization later)

See merge request core-developers/forge!3033

forge-game/src/main/java/forge/game/cost/CostPartWithList.java

@@ -132,8 +132,8 @@ public abstract class CostPartWithList extends CostPart {
             }
             cardList.addAll(doListPayment(ability, targetCards));
         } else {
-            if (targetCards.isEmpty()) {
-                doPayment(ability, null); // e.g. CostFlipCoin
+            if (targetCards.isEmpty() && this instanceof CostFlipCoin) {
+                doPayment(ability, null); // TODO: generalize for other cost types if necessary
             } else {
                 for (Card c : targetCards) {
                     executePayment(ability, c);