Mark file-writer-events-shared-worker.html as flaky on win7 debug

BUG=321857
TEST=
[email protected]

Review URL: https://codereview.chromium.org/79363005

git-svn-id: svn://svn.chromium.org/blink/trunk@162426 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index 37e0da10..f761043 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -579,3 +579,4 @@
 
 crbug.com/321787 [ Win ] virtual/gpu/fast/canvas/webgl/premultiplyalpha-test.html [ Pass Failure ]
 crbug.com/321793 [ Win ] fast/frames/sandboxed-iframe-navigation-windowopen.html [ Pass Timeout ]
+crbug.com/321857 [ Win7 Debug ] fast/filesystem/workers/file-writer-events-shared-worker.html [ Pass Failure ]