Mark gc-dom-tree-lifetime as flaky timeout

TBR=kouhei@chromium.org
BUG=356828

Review URL: https://codereview.chromium.org/212953009

git-svn-id: svn://svn.chromium.org/blink/trunk@170095 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -876,6 +876,8 @@ crbug.com/349537 virtual/stable/http/tests/websocket/workers/worker-reload-repea
 
 crbug.com/339778 [ Debug ] fast/dom/timer-throttling-hidden-page.html [ Failure Pass ]
 
+crbug.com/356828 fast/dom/gc-dom-tree-lifetime.html [ Timeout Pass ]
+
 # Heap buffer overflow failures on Linux ASAN
 crbug.com/347365 [ Linux ] dom/xhtml/level3/core/canonicalform08.xhtml [ Crash Pass ]
 crbug.com/347365 [ Linux ] dom/xhtml/level3/core/canonicalform09.xhtml [ Crash Pass ]