Mark fast/forms/validation-bubble-* as failure on Mac 10.{10,11}

TBR=wangxianzhu@chromium.org

Bug: 943907
No-Try: True
Change-Id: I603abad7d311f62431cfec20a3bb84ea7527d8fd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1531218Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#642366}

third_party/blink/web_tests/TestExpectations

@@ -6124,3 +6124,7 @@ crbug.com/938592 virtual/gpu/fast/canvas/fillrect_gradient.html [ Pass Failure T
 # Trooper 2019-03-19
 crbug.com/836242 [ Mac ] external/wpt/shadow-dom/untriaged/html-elements-in-shadow-trees/html-forms/test-003.html [ Pass Failure ]
 
+# Sheriff 2019-03-20
+crbug.com/943907 [ Mac10.10 Mac10.11 ] fast/forms/validation-bubble-appearance-escape.html [ Pass Failure ]
+crbug.com/943907 [ Mac10.10 Mac10.11 ] fast/forms/validation-bubble-device-emulation-change.html [ Pass Failure ]
+crbug.com/943907 [ Mac10.10 Mac10.11 ] fast/forms/validation-bubble-device-emulation.html [ Pass Failure ]