[iOS] Disable testXClientData

The test is failing for all config.

TBR=stkhapugin@chromium.org

Bug: 1036225
Change-Id: I3f9de1775e5be694c7131bf2cce18571324cc375
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1985000Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727868}

ios/chrome/browser/ui/omnibox/omnibox_egtest.mm

@@ -144,13 +144,8 @@ id<GREYMatcher> SearchCopiedTextButton() {
 
 // Tests that the XClientData header is sent when navigating to
 // https://google.com through the omnibox.
-- (void)testXClientData {
-#if !TARGET_IPHONE_SIMULATOR
-  // TODO(crbug.com/1036225): Test flaky on iOS 12 device.
-  if (!base::ios::IsRunningOnIOS13OrLater()) {
-    EARL_GREY_TEST_DISABLED(@"Flaky on iOS 12 device.");
-  }
-#endif
+// TODO(crbug.com/1036225): Test very flaky on all config.
+- (void)DISABLED_testXClientData {
   // Rewrite the google URL to localhost URL.
   [OmniboxAppInterface rewriteGoogleURLToLocalhost];