Mark a test as expected to fail on Win7 dbg.

BUG=728895
TEST=none
TBR=wangxianzhu

Change-Id: I1086a24605c4597962da3247f6d2404a7aef651a
Reviewed-on: https://chromium-review.googlesource.com/522343Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476530}

third_party/WebKit/LayoutTests/TestExpectations

@@ -2996,3 +2996,6 @@ crbug.com/728036 [ Linux Mac Win ] virtual/threaded/fast/compositorworker/compos
 crbug.com/727505 [ Linux Mac Win ] virtual/threaded/fast/compositorworker/basic-plumbing-main-to-worker.html [ Pass Failure Timeout Crash ]
 crbug.com/727505 [ Linux Mac Win ] virtual/threaded/fast/compositorworker/basic-plumbing-worker-to-main.html [ Pass Failure Timeout Crash ]
 crbug.com/727505 [ Linux Mac Win ] virtual/threaded/fast/compositorworker/request-animation-frame.html [ Pass Failure Timeout Crash ]
+
+crbug.com/728895 [ Win7 Debug ] fast/table/backgr_border-table-column-group-collapsed-border.html [ Failure ]
+crbug.com/728895 [ Win7 Debug ] virtual/mojo-loading/fast/table/backgr_border-table-column-group-collapsed-border.html [ Failure ]
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