[iOS] Removing flaky tets

Removing flaky test as it is not particularly useful. There is a similar
test doing the same (LastTimePasswordCheckCompletedReset).

Bug: 1148791
Change-Id: Id82a00300f02336e9091d33bbd3999d78ffe4f18
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2540606Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Viktor Semeniuk <vsemeniuk@google.com>
Cr-Commit-Position: refs/heads/master@{#827834}

ios/chrome/browser/passwords/ios_chrome_password_check_manager_unittest.mm

@@ -264,17 +264,6 @@ TEST_F(IOSChromePasswordCheckManagerTest,
   EXPECT_EQ(base::Time(), manager().GetLastPasswordCheckTime());
 }
 
-// Checks that a non-default kLastTimePasswordCheckCompleted pref value is
-// treated as a completed run.
-TEST_F(IOSChromePasswordCheckManagerTest, LastTimePasswordCheckCompletedIsSet) {
-  base::Time expected = base::Time::Now() - base::TimeDelta::FromMinutes(5);
-  browser_state()->GetPrefs()->SetDouble(
-      password_manager::prefs::kLastTimePasswordCheckCompleted,
-      expected.ToDoubleT());
-
-  EXPECT_THAT(expected, manager().GetLastPasswordCheckTime());
-}
-
 // Checks that a transition into the idle state after starting a check results
 // in resetting the kLastTimePasswordCheckCompleted pref to the current time.
 TEST_F(IOSChromePasswordCheckManagerTest, LastTimePasswordCheckCompletedReset) {