Disable flaky test overflow-positioning.html on Win7 Debug.

third_party/WebKit/LayoutTests/TestExpectations

Index: third_party/WebKit/LayoutTests/TestExpectations
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index 3c931727afe29294cd61bbb827b457bf1b65afbe..ce7637b0af5b76eafa30466fd36724eaba939a8b 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -2352,15 +2352,18 @@ crbug.com/685951 css2.1/t040304-c64-uri-00-a-g.html [ Failure Pass ]
 
 skbug.com/6203 [ Mac ] fast/forms/text/text-font-height-mismatch.html [ NeedsManualRebaseline ]
 
-# Sheriff failures Feb 03 2017
+# Sheriff failures 2017-02-03
 crbug.com/688515 fast/spatial-navigation/snav-div-overflow-scrol-hidden.html [ Pass Failure ]
 
 # Flaky on trybots
 crbug.com/688486 external/wpt/service-workers/service-worker/fetch-request-redirect.https.html [ Failure Pass ]
 crbug.com/688486 external/wpt/service-workers/service-worker/fetch-request-resources.https.html [ Failure Pass ]
 
-# Sheriff failures Feb 06 2017
+# Sheriff failures 2017-02-06
 crbug.com/688515 [ Linux ] http/tests/media/video-play-stall.html [ Pass Failure ]
 
-# Sheriff failures Feb 13 2017
+# Sheriff failures 2017-02-13
 crbug.com/691423 [ Mac ] fast/frames/location-change-no-file-access.html [ Failure Pass ]
+
+# Sheriff failures 2017-02-16
+crbug.com/692733 [ Win7 Debug ] compositing/overflow/overflow-positioning.html [ Failure Pass ]