Follow-up fix after r371372

I forgot to add [Leak] when landing r371372.

BUG=
TBR=yosin@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1636963002

Cr-Commit-Position: refs/heads/master@{#371468}

third_party/WebKit/LayoutTests/LeakExpectations

@@ -155,4 +155,4 @@ crbug.com/578297 [ Linux ] http/tests/media/media-source/mediasource-appendstrea
 # -----------------------------------------------------------------
 # Temmporary leaks that must be fixed in a reasonable timeline.
 # -----------------------------------------------------------------
-crbug.com/581210 editing/execCommand/outdent-collapse-table-crash.html
+crbug.com/581210 editing/execCommand/outdent-collapse-table-crash.html [ Leak ]