Mark WUT#testDeserializeSearchRequests awaits fix

This commit marks WatcherUtilsTests#testDeserializeSearchRequest which
is failing with seed 2203D3AD59DB5223 as awaits fix.

Original commit: elastic/x-pack-elasticsearch@4b6cbe544b

elasticsearch/x-pack/watcher/src/test/java/org/elasticsearch/xpack/watcher/support/WatcherUtilsTests.java

@@ -136,6 +136,7 @@ public class WatcherUtilsTests extends ESTestCase {
 
     }
 
+    @AwaitsFix(bugUrl = "https://github.com/elastic/x-plugins/issues/3136")
     public void testDeserializeSearchRequest() throws Exception {
 
         XContentBuilder builder = jsonBuilder().startObject();