Re-enable stable tests in StartSurfaceTests

In crrev.com/c/2314297, the following tests were disabled because they
were flaky on emulators:
- StartSurfaceTest#testScroll_Top__NoInstant_Return
- StartSurfaceTest#testScroll_Top__Instant_Return
- StartSurfaceTest#testScroll_Quick__NoInstant_Return
- StartSurfaceTest#testScroll_Quick__Instant_Return

They are re-enabled on builders like android-pie-arm64-rel.

Bug: 1108459
Change-Id: I3f66a184db1e292a3f98c7a647d9cc23ab42b276
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2314875
Commit-Queue: Yue Zhang <yuezhanggg@chromium.org>
Reviewed-by: Yue Zhang <yuezhanggg@chromium.org>
Auto-Submit: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791253}

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

@@ -863,9 +863,9 @@ public class StartSurfaceTest {
     @Feature({"StartSurface"})
     // clang-format off
     @DisableIf.Build(hardware_is = "bullhead", message = "crbug.com/1081657")
+    @DisableIf.Build(supported_abis_includes = "x86", message = "https://crbug.com/1108459")
     @CommandLineFlags.Add({BASE_PARAMS + "/omniboxonly" +
         "/hide_switch_when_no_incognito_tabs/true/omnibox_scroll_mode/top"})
-    @DisabledTest(message = "https://crbug.com/1108459")
     public void testScroll_Top() {
         // clang-format on
         // TODO(crbug.com/1082664): Make it work with NoReturn.
@@ -890,9 +890,9 @@ public class StartSurfaceTest {
     @Feature({"StartSurface"})
     // clang-format off
     @DisableIf.Build(sdk_is_less_than = P, message = "crbug.com/1083174")
+    @DisableIf.Build(supported_abis_includes = "x86", message = "https://crbug.com/1108459")
     @CommandLineFlags.Add({BASE_PARAMS + "/omniboxonly" +
         "/hide_switch_when_no_incognito_tabs/true/omnibox_scroll_mode/quick"})
-    @DisabledTest(message = "https://crbug.com/1108459")
     public void testScroll_Quick() {
         // clang-format on
         // TODO(crbug.com/1082664): Make it work with NoReturn.