Disable flaky test LeaveSiteStillWarnsAfter on Windows

SafetyTipPageInfoBubbleViewBrowserTest.LeaveSiteStillWarnsAfter is
flaky on Windows,
https://ci.chromium.org/p/chromium/builders/ci/Win10%20Tests%20x64,
disable it for now until it is fixed.

TBR=jdeblasio@chromium.org
NOTRY=True

Bug: 1140193
Change-Id: I0245b63bbe209d8c65f8c94ca6117a552670db53
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2486252Reviewed-by: Lan Wei <lanwei@chromium.org>
Commit-Queue: Lan Wei <lanwei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818643}

chrome/browser/ui/views/page_info/safety_tip_page_info_bubble_view_browsertest.cc

@@ -627,7 +627,7 @@ IN_PROC_BROWSER_TEST_P(SafetyTipPageInfoBubbleViewBrowserTest,
 // If the user clicks 'leave site', the warning should re-appear when the user
 // re-visits the page.
 // Flaky on Mac: https://crbug.com/1139955
-#if defined(OS_MAC)
+#if defined(OS_MAC) || defined(OS_WIN)
 #define MAYBE_LeaveSiteStillWarnsAfter DISABLED_LeaveSiteStillWarnsAfter
 #else
 #define MAYBE_LeaveSiteStillWarnsAfter LeaveSiteStillWarnsAfter