[iOS] Disable failing tests.

Disables the following tests:
FormsTestCase / testPostFormEntryWithKeyboard
TabOrderTestCase / testChildTabOrdering

Bug: 1106741, 1106739
Change-Id: I61f2f1ded92223d8ce25fcd5a7c08ba33ad68afa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2304583
Auto-Submit: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789491}

ios/chrome/browser/web/forms_egtest.mm

@@ -528,7 +528,8 @@ id<GREYMatcher> ResendPostButtonMatcher() {
 // Tests that submitting a POST-based form by tapping the 'Go' button on the
 // keyboard navigates to the correct URL and the back button works as expected
 // afterwards.
-- (void)testPostFormEntryWithKeyboard {
+// TODO(crbug.com/1106741): reenable this test.
+- (void)DISABLED_testPostFormEntryWithKeyboard {
   // Test fails on iPad Air 2 13.4 crbug.com/1102608.
   if ([ChromeEarlGrey isIPadIdiom] && base::ios::IsRunningOnOrLater(13, 0, 0)) {
     EARL_GREY_TEST_DISABLED(@"Fails in iOS 13 on iPads.");

ios/chrome/browser/web/tab_order_egtest.mm

@@ -47,7 +47,8 @@ const char kLinksTestURL2Text[] = "arrived";
 @implementation TabOrderTestCase
 
 // Tests that new tabs are always inserted after their parent tab.
-- (void)testChildTabOrdering {
+// TODO(crbug.com/1106739): reenable this test.
+- (void)DISABLED_testChildTabOrdering {
   GREYAssertTrue(self.testServer->Start(), @"Test server failed to start.");
   const GURL URL1 = self.testServer->GetURL(kLinksTestURL1);