Fix flaky RenderDocumentHostUserData::FailedNavigation test

This CL fixes the flakiness caused by the
RenderDocumentHostUserData::FailedNavigation test case.

Bug: 1065495
Change-Id: I9a37af49bd9549587d9df6e2855277c488efe9c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2132137Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Sreeja Kamishetty <sreejakshetty@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759984}

content/browser/frame_host/render_document_host_user_data_browsertest.cc

@@ -410,9 +410,7 @@ IN_PROC_BROWSER_TEST_F(RenderDocumentHostUserDataTest, CancelledNavigation) {
 
 // Tests that RenderDocumentHostUserData object is cleared when a failed
 // navigation results in an error page.
-// TODO(crbug.com/1065495): Fix the test flakiness.
-IN_PROC_BROWSER_TEST_F(RenderDocumentHostUserDataTest,
-                       DISABLED_FailedNavigation) {
+IN_PROC_BROWSER_TEST_F(RenderDocumentHostUserDataTest, FailedNavigation) {
   // This test is only valid if error page isolation is enabled.
   if (!SiteIsolationPolicy::IsErrorPageIsolationEnabled(true))
     return;