[hotfix][tests] Disable alignment timeout by default in UnalignedCheckpointITCase

Most of the bugs in UC are revealed with higher back-pressure which is not created with alignment timeout.
This change disables it by default and adds a new test (p=20) with the timeout enabled.

flink-tests/src/test/java/org/apache/flink/test/checkpointing/UnalignedCheckpointITCase.java

@@ -119,6 +119,10 @@ public class UnalignedCheckpointITCase extends UnalignedCheckpointTestBase {
                 "parallel pipeline with mixed channels, p = 20",
                 createPipelineSettings(20, 10, true)
             },
+            new Object[] {
+                "parallel pipeline with mixed channels, p = 20, timeout=1",
+                createPipelineSettings(20, 10, true, 1)
+            },
             new Object[] {"Parallel cogroup, p = 5", createCogroupSettings(5)},
             new Object[] {"Parallel cogroup, p = 10", createCogroupSettings(10)},
             new Object[] {"Parallel union, p = 5", createUnionSettings(5)},
@@ -128,6 +132,11 @@ public class UnalignedCheckpointITCase extends UnalignedCheckpointTestBase {
 
     private static UnalignedSettings createPipelineSettings(
             int parallelism, int slotsPerTaskManager, boolean slotSharing) {
+        return createPipelineSettings(parallelism, slotsPerTaskManager, slotSharing, 0);
+    }
+
+    private static UnalignedSettings createPipelineSettings(
+            int parallelism, int slotsPerTaskManager, boolean slotSharing, int timeout) {
         int numShuffles = 4;
         return new UnalignedSettings(UnalignedCheckpointITCase::createPipeline)
                 .setParallelism(parallelism)
@@ -135,7 +144,8 @@ public class UnalignedCheckpointITCase extends UnalignedCheckpointTestBase {
                 .setNumSlots(slotSharing ? parallelism : parallelism * numShuffles)
                 .setNumBuffers(getNumBuffers(parallelism, numShuffles))
                 .setSlotsPerTaskManager(slotsPerTaskManager)
-                .setExpectedFailures(5);
+                .setExpectedFailures(5)
+                .setAlignmentTimeout(timeout);
     }
 
     private static UnalignedSettings createCogroupSettings(int parallelism) {

flink-tests/src/test/java/org/apache/flink/test/checkpointing/UnalignedCheckpointTestBase.java

@@ -516,6 +516,7 @@ public abstract class UnalignedCheckpointTestBase extends TestLogger {
         private int numBuffers;
         private int expectedFailures = 0;
         private final DagCreator dagCreator;
+        private int alignmentTimeout = 0;
 
         public UnalignedSettings(DagCreator dagCreator) {
             this.dagCreator = dagCreator;
@@ -561,6 +562,11 @@ public abstract class UnalignedCheckpointTestBase extends TestLogger {
             return this;
         }
 
+        public UnalignedSettings setAlignmentTimeout(int alignmentTimeout) {
+            this.alignmentTimeout = alignmentTimeout;
+            return this;
+        }
+
         public StreamExecutionEnvironment createEnvironment(File checkpointDir) {
             Configuration conf = new Configuration();
 
@@ -591,7 +597,7 @@ public abstract class UnalignedCheckpointTestBase extends TestLogger {
             final LocalStreamEnvironment env =
                     StreamExecutionEnvironment.createLocalEnvironment(parallelism, conf);
             env.enableCheckpointing(100);
-            env.getCheckpointConfig().setAlignmentTimeout(1);
+            env.getCheckpointConfig().setAlignmentTimeout(alignmentTimeout);
             env.setParallelism(parallelism);
             env.setRestartStrategy(
                     RestartStrategies.fixedDelayRestart(