Mark STT#testParser as awaits fix

This commit marks SearchTransformTests#testParser which is failing with
seed 97BC9E2543410D55 as awaits fix.

Original commit: elastic/x-pack-elasticsearch@3d69e9648c

elasticsearch/x-pack/watcher/src/test/java/org/elasticsearch/xpack/watcher/test/integration/SearchTransformTests.java

@@ -183,6 +183,7 @@ public class SearchTransformTests extends ESIntegTestCase {
         }
     }
 
+    @AwaitsFix(bugUrl = "https://github.com/elastic/x-plugins/issues/3135")
     public void testParser() throws Exception {
         String[] indices = rarely() ? null : randomBoolean() ? new String[] { "idx" } : new String[] { "idx1", "idx2" };
         SearchType searchType = getRandomSupportedSearchType();