Disable two test cases in StartSurfaceLayoutTest.

These are failing on recent builds.
StartSurfaceLayoutTest.testThumbnailAspectRatio_default.
StartSurfaceLayoutTest.testThumbnailAspectRatio_point75.

TBR=wychen@chromium.org

Bug: 1122657
Change-Id: Ib68765728b77dbb08c23d81667a2eb680231781a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2380199Reviewed-by: Xing Liu <xingliu@chromium.org>
Commit-Queue: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#802383}

chrome/android/features/start_surface/internal/javatests/src/org/chromium/chrome/features/start_surface/StartSurfaceLayoutTest.java

@@ -1077,6 +1077,7 @@ public class StartSurfaceLayoutTest {
     @Test
     @MediumTest
     @CommandLineFlags.Add({BASE_PARAMS})
+    @DisabledTest(message = "https://crbug.com/1122657")
     public void testThumbnailAspectRatio_default() {
         prepareTabs(2, 0, mUrl);
         enterTabSwitcher(mActivityTestRule.getActivity());
@@ -1087,6 +1088,7 @@ public class StartSurfaceLayoutTest {
     @Test
     @MediumTest
     @CommandLineFlags.Add({BASE_PARAMS + "/thumbnail_aspect_ratio/0.75"})
+    @DisabledTest(message = "https://crbug.com/1122657")
     public void testThumbnailAspectRatio_point75() {
         prepareTabs(2, 0, mUrl);
         enterTabSwitcher(mActivityTestRule.getActivity());