Disable flaky tests in ContextualSearchManagerTest.java suite

BUG=673681
TBR=donnd@chromium.org,twellington@chromium.org

Review-Url: https://codereview.chromium.org/2571783002
Cr-Commit-Position: refs/heads/master@{#438180}

chrome/android/javatests/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManagerTest.java

@@ -2739,6 +2739,7 @@ public class ContextualSearchManagerTest extends ChromeActivityTestCaseBase<Chro
      */
     @SmallTest
     @Feature({"ContextualSearch"})
+    @RetryOnFailure  // crbug.com/673681
     public void testQuickActionCaptionAndImage() throws InterruptedException, TimeoutException {
         // Simulate a tap to show the Bar, then set the quick action data.
         simulateTapSearch("search");