Mark network-xhr-same-url-as-main-resource.js as flaky on Win10

TBR=chenwilliam@chromium.org

Bug: 785980
Change-Id: Ib61f79451a99c1a98f061e4f32acd2337d55707a
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/774859
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517099}

third_party/WebKit/LayoutTests/TestExpectations

@@ -4112,3 +4112,7 @@ crbug.com/785187 [ Linux ] virtual/mojo-loading/http/tests/devtools/elements/ele
 crbug.com/785187 [ Mac ] http/tests/devtools/elements/elements-panel-rewrite-href.js [ Failure Pass ]
 crbug.com/785662 [ Debug ] http/tests/devtools/sources/debugger-ui/reveal-not-skipped.js [ Failure Pass ]
 crbug.com/785662 [ Debug ] virtual/mojo-loading/http/tests/devtools/sources/debugger-ui/reveal-not-skipped.js [ Failure Pass ]
+
+# Sheriff failures 2017-11-16
+crbug.com/785980 [ Win10 ] virtual/mojo-loading/http/tests/devtools/network/network-xhr-same-url-as-main-resource.js [ Failure Pass ]
+crbug.com/785980 [ Win10 ] http/tests/devtools/network/network-xhr-same-url-as-main-resource.js [ Failure Pass ]