Correctly disable flaky tests on device.

These tests are not failed on simulator and should only be disabled on
devices. Also Added TODOs that reference the bugs.

Bug: 954231, 954232
Change-Id: If1aa247e5686211187fddbc1b82c8051f71ab4d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574287
Auto-Submit: Eugene But <eugenebut@chromium.org>
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#652552}

ios/web/web_state/error_page_inttest.mm

@@ -134,7 +134,13 @@ class ErrorPageTest
 
 // Tests that the error page is correctly displayed after navigating back to it
 // multiple times. See http://crbug.com/944037 .
-TEST_P(ErrorPageTest, FLAKY_BackForwardErrorPage) {
+// TODO(crbug.com/954231): this test is flaky on device.
+#if TARGET_IPHONE_SIMULATOR
+#define MAYBE_BackForwardErrorPage BackForwardErrorPage
+#else
+#define MAYBE_BackForwardErrorPage FLAKY_BackForwardErrorPage
+#endif
+TEST_P(ErrorPageTest, MAYBE_BackForwardErrorPage) {
   test::LoadUrl(web_state(), server_.GetURL("/close-socket"));
   ASSERT_TRUE(WaitForErrorText(web_state(), server_.GetURL("/close-socket")));
 

ios/web/web_state/web_state_observer_inttest.mm

@@ -2034,7 +2034,13 @@ TEST_P(WebStateObserverTest, DownloadNavigation) {
 }
 
 // Tests failed load after the navigation is sucessfully finished.
-TEST_P(WebStateObserverTest, FLAKY_FailedLoad) {
+// TODO(crbug.com/954232): this test is flaky on device.
+#if TARGET_IPHONE_SIMULATOR
+#define MAYBE_FailedLoad FailedLoad
+#else
+#define MAYBE_FailedLoad FLAKY_FailedLoad
+#endif
+TEST_P(WebStateObserverTest, MAYBE_FailedLoad) {
   GURL url = test_server_->GetURL("/exabyte_response");
 
   NavigationContext* context = nullptr;