Temporarily disable flaky test

Disables SubresourceFilterBrowserTest.
PopupWithDocWriteAbortedLoadAndOpenerClosed_FilterChecked, which is
flaky after recent changes in crrev.com/c/2515181. It appears the
original test did not always have the expected sequence of navigations.

Change-Id: I7fe3b2b5d5a181a69b86202b79853318a212dd94
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532968
Commit-Queue: Alex Turner <alexmt@chromium.org>
Commit-Queue: Charlie Harrison <csharrison@chromium.org>
Auto-Submit: Alex Turner <alexmt@chromium.org>
Reviewed-by: Charlie Harrison <csharrison@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826473}

chrome/browser/subresource_filter/subresource_filter_browsertest.cc

@@ -943,9 +943,10 @@ IN_PROC_BROWSER_TEST_F(SubresourceFilterBrowserTest,
 // Test that resources in a popup with an aborted initial load due to a
 // doc.write are still blocked when disallowed, even if the opener is
 // immediately closed after writing.
+// TODO(alexmt): Fix test flakiness and then reenable.
 IN_PROC_BROWSER_TEST_F(
     SubresourceFilterBrowserTest,
-    PopupWithDocWriteAbortedLoadAndOpenerClosed_FilterChecked) {
+    DISABLED_PopupWithDocWriteAbortedLoadAndOpenerClosed_FilterChecked) {
   ASSERT_NO_FATAL_FAILURE(
       SetRulesetWithRules({testing::CreateSuffixRule("ad_script.js"),
                            testing::CreateSuffixRule("ad=true")}));