[Sheriff] Disable AppListPresenterDelegateTest.AppListShownWhileClosing

flaky test.

TBR="xiyuan@chromium.org, tbarzic@chromium.org"

Bug: 1056302
Change-Id: I65cbd1acadb5e68e3394f7cfeb7fa491f8c0abf5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2076377Reviewed-by: Parastoo Geranmayeh <parastoog@google.com>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Parastoo Geranmayeh <parastoog@google.com>
Cr-Commit-Position: refs/heads/master@{#744805}

ash/app_list/app_list_presenter_delegate_unittest.cc

@@ -1230,10 +1230,11 @@ TEST_F(AppListPresenterDelegateTest, ShelfBackgroundWithHomeLauncher) {
             shelf_layout_manager->GetShelfBackgroundType());
 }
 
+// Flaky test: crbug/1056302
 // Tests that app list understands shelf rounded corners state while animating
 // out and in, and that it keeps getting notified of shelf state changes if
 // close animation is interrupted by another show request.
-TEST_F(AppListPresenterDelegateTest, AppListShownWhileClosing) {
+TEST_F(AppListPresenterDelegateTest, DISABLED_AppListShownWhileClosing) {
   auto window = CreateTestWindow();
   window->SetProperty(aura::client::kShowStateKey, ui::SHOW_STATE_MAXIMIZED);