[iOS] Disable flaky testIncognitoSeparation and testMultiplePageOpened.

These two eg2 tests are disabled because they broke 15% of recent
ios-simulator-noncq builds and will block iOS code submission after EG2
tests run in CQ. The failure happens mostly on iOS 12.4 but also
sometimes on 13.3 so the test method is just disabled.

Bug: 1046369
Change-Id: I4b30abcea7be5aef995f24e0ce407f2df92e3514
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2129108Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Zhaoyang Li <zhaoyangli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#755029}

ios/chrome/browser/ui/omnibox/popup/omnibox_popup_egtest.mm

@@ -163,8 +163,9 @@ std::unique_ptr<net::test_server::HttpResponse> StandardResponse(
 }
 
 // Tests that the incognito tabs aren't displayed as "opened" tab in the
-// non-incognito suggestions and vice-versa.
-- (void)testIncognitoSeparation {
+// non-incognito suggestions and vice-versa. TODO(crbug.com/1059464): Test is
+// flaky.
+- (void)DISABLED_testIncognitoSeparation {
   GURL URL1 = self.testServer->GetURL(kPage1URL);
   GURL URL2 = self.testServer->GetURL(kPage2URL);
   GURL URL3 = self.testServer->GetURL(kPage3URL);
@@ -322,8 +323,8 @@ std::unique_ptr<net::test_server::HttpResponse> StandardResponse(
 }
 
 // Tests that having multiple suggestions with corresponding opened tabs display
-// multiple buttons.
-- (void)testMultiplePageOpened {
+// multiple buttons. TODO(crbug.com/1059464): Test is flaky.
+- (void)DISABLED_testMultiplePageOpened {
   // Open the first page.
   GURL URL1 = self.testServer->GetURL(kPage1URL);
   [ChromeEarlGrey loadURL:URL1];