minor #38912 Fix transiant tests (jderusse)

This PR was merged into the 5.2-dev branch.

Discussion
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Fix transiant tests

| Q             | A
| ------------- | ---
| Branch?       | 5.x
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

I've seen 1 occurency of this failure, because of rounded time(), the delay where 2 minutes instead of 1

Commits
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890b16d36d Fix transiant tests

src/Symfony/Bundle/SecurityBundle/Tests/Functional/FormLoginTest.php

@@ -110,6 +110,7 @@ class FormLoginTest extends AbstractWebTestCase
 
     /**
      * @dataProvider provideInvalidCredentials
+     * @group time-sensitive
      */
     public function testLoginThrottling($username, $password)
     {