Mute RegressionIT.testStopAndRestart test case as I've found it reproducible locally. (#49167)

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

@@ -239,6 +239,7 @@ public class RegressionIT extends MlNativeDataFrameAnalyticsIntegTestCase {
             "Finished analysis");
     }
 
+    @AwaitsFix(bugUrl="https://github.com/elastic/elasticsearch/issues/49095")
     public void testStopAndRestart() throws Exception {
         initialize("regression_stop_and_restart");