AI, tests: added stability tests to make sure AI simulations can process errors and freezes (part of #13638, #13766);

Mage.Server.Plugins/Mage.Player.AIMCTS/src/mage/player/ai/ComputerPlayerMCTS.java

@@ -196,7 +196,7 @@ public class ComputerPlayerMCTS extends ComputerPlayer {
                 } catch (ExecutionException e) {
                     // real games: must catch and log
                     // unit tests: must raise again for fast fail
-                    if (this.isTestsMode()) {
+                    if (this.isTestMode() && this.isFastFailInTestMode()) {
                         throw new IllegalStateException("One of the simulated games raise the error: " + e, e);
                     }
                 }