Attempt to combat game memory leaks after game finishes.

- Make PLAY_LAND_SURROGATE a game field rather than static
- Remove games from cache more aggressively
- Remove targeting overlay from global view after game ends

forge-gui-desktop/src/main/java/forge/screens/match/CMatchUI.java

@@ -813,6 +813,7 @@ public final class CMatchUI
 
     @Override
     public void afterGameEnd() {
+        Singletons.getView().getLpnDocument().remove(targetingOverlay.getPanel());
         FThreads.invokeInEdtNowOrLater(new Runnable() {
             @Override public void run() {
                 Singletons.getView().getNavigationBar().closeTab(screen);