Disable ScreenOrientationListenerTest#testFlipLandscape, which is flaky.

BUG=647058,645609
TBR=mlamouri@chromium.org

Review-Url: https://codereview.chromium.org/2341073002
Cr-Commit-Position: refs/heads/master@{#418872}

content/public/android/javatests/src/org/chromium/content/browser/ScreenOrientationListenerTest.java

@@ -206,6 +206,7 @@ public class ScreenOrientationListenerTest extends ContentShellTestBase {
         assertTrue(checkOrientationForLock(ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT));
     }
 
+    @DisabledTest(message = "crbug.com/645609")
     @MediumTest
     @Feature({"ScreenOrientation"})
     @RetryOnFailure