Mark some interactive ui tests as flaky on Windows.
See:
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/41603
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/41598
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/41597
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/41586
https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/41601
TBR=pauljensen@chromium.org
BUG=523255
Review URL: https://codereview.chromium.org/
1329293002
Cr-Commit-Position: refs/heads/master@{#347970}