Disable flaky MetricsWebContentsObserverTest.MainFrameNavigationInternalAbort

TBR=csharrison@chromium.org

Bug: 1011201
Change-Id: Iae56e7204659d4a94208ed024b68610739e62557
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1839152Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Auto-Submit: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702684}

components/page_load_metrics/browser/metrics_web_contents_observer_unittest.cc

@@ -282,7 +282,8 @@ TEST_F(MetricsWebContentsObserverTest, SuccessfulMainFrameNavigation) {
   CheckNoErrorEvents();
 }
 
-TEST_F(MetricsWebContentsObserverTest, MainFrameNavigationInternalAbort) {
+TEST_F(MetricsWebContentsObserverTest,
+       DISABLED_MainFrameNavigationInternalAbort) {
   content::WebContentsTester* web_contents_tester =
       content::WebContentsTester::For(web_contents());
   web_contents_tester->NavigateAndFail(