Mute testStopAndRestart test case (#50551)

x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/RegressionIT.java

@@ -183,6 +183,7 @@ public void testWithOnlyTrainingRowsAndTrainingPercentIsFifty() throws Exception
             "Finished analysis");
     }
 
+    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/49680")
     public void testStopAndRestart() throws Exception {
         initialize("regression_stop_and_restart");
         indexData(sourceIndex, 350, 0);