Disable FLAKY test WorkaroundCrashySierra

Full test name is
SSLClientCertificateSelectorCocoaTest.WorkaroundCrashySierra

Test only runs (and flakes) on mac.

Bug: 810909
Change-Id: I2dc0c8d347a8292d89df3e5590cfff1db481829a
TBR: sdy@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/920685Reviewed-by: Chrome Cunningham <chcunningham@chromium.org>
Commit-Queue: Chrome Cunningham <chcunningham@chromium.org>
Cr-Commit-Position: refs/heads/master@{#536918}

chrome/browser/ui/cocoa/ssl_client_certificate_selector_cocoa_browsertest.mm

@@ -290,8 +290,9 @@ IN_PROC_BROWSER_TEST_F(SSLClientCertificateSelectorCocoaTest, HideShow) {
 @end
 
 // Test that we can't trigger the crash from https://crbug.com/653093
+// Disabled due to flakiness. http://crbug.com/810909
 IN_PROC_BROWSER_TEST_F(SSLClientCertificateSelectorCocoaTest,
-                       WorkaroundCrashySierra) {
+                       DISABLED_WorkaroundCrashySierra) {
   BOOL selector_was_deallocated = false;
 
   @autoreleasepool {