[iOS] Disabled flaky SigninCoordinatorTestCase on Simulators

TBR=fernandex@chromium.org

Bug: 1146459
Change-Id: I4b8163481ee473e049cb54504698dc08fbc5a466
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2521707Reviewed-by: Sebastien Lalancette <seblalancette@chromium.org>
Commit-Queue: Sebastien Lalancette <seblalancette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824912}

ios/chrome/browser/ui/authentication/signin/signin_coordinator_egtest.mm

@@ -556,7 +556,15 @@ void ChooseImportOrKeepDataSepareteDialog(id<GREYMatcher> choiceButtonMatcher) {
 // choosing UI. Depending on the timing, the account removal may occur after
 // the UI has retrieved the list of valid accounts. The test ensures that in
 // this case no account is presented to the user.
-- (void)testAccountInvalidatedDuringSignin {
+// TODO(crbug.com/1146459): Test is flaky on simulators.
+#if TARGET_IPHONE_SIMULATOR
+#define MAYBE_testAccountInvalidatedDuringSignin \
+  DISABLED_testAccountInvalidatedDuringSignin
+#else
+#define MAYBE_testAccountInvalidatedDuringSignin \
+  testAccountInvalidatedDuringSignin
+#endif
+- (void)MAYBE_testAccountInvalidatedDuringSignin {
   FakeChromeIdentity* fakeIdentity = [SigninEarlGrey fakeIdentity1];
   [SigninEarlGrey addFakeIdentity:fakeIdentity];