[Sheriff][Android] Disable StartSurfaceTest#testHomeButton_OpenNTPInsteadOfStart

Reason: flaky.

Builder links:
https://ci.chromium.org/p/chromium/builders/ci/Marshmallow%2064%20bit%20Tester/33134
https://ci.chromium.org/p/chromium/builders/ci/Marshmallow%2064%20bit%20Tester/33135

TBR=wychen@chromium.org

Bug: 1119322
Change-Id: Icf1cd4dcd2424c3aadf24b508ed25f3f02c406fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2362926Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#799584}

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

@@ -835,6 +835,7 @@ public class StartSurfaceTest {
     @MediumTest
     @Feature({"StartSurface"})
     // clang-format off
+    @DisableIf.Build(hardware_is = "bullhead", message = "https://crbug.com/1119322")
     @CommandLineFlags.Add({BASE_PARAMS + "/single/open_ntp_instead_of_start/true"})
     public void testHomeButton_OpenNTPInsteadOfStart() {
         // clang-format on