Mark inspector/layers/layer-canvas-log.html as flaky.

BUG=381471
TBR=peter@chromium.org

Review URL: https://codereview.chromium.org/317283002

git-svn-id: svn://svn.chromium.org/blink/trunk@175605 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -999,6 +999,8 @@ crbug.com/371651 svg/custom/use-disappears-after-style-update.svg [ Pass Failure
 crbug.com/371651 svg/filters/filter-refresh.svg [ Failure ]
 crbug.com/371651 svg/text/text-text-05-t.svg [ Failure ]
 
+crbug.com/381471 inspector/layers/layer-canvas-log.html [ Pass Failure ]
+
 crbug.com/371654 fast/html/imports/import-custom-element-dup-resolve.html [ Pass Failure ]
 
 crbug.com/381464 fast/dom/Window/Location/window-shadow-location-using-string.html [ Pass Failure ]