minor #23172 Fix AutowiringTypesTest transient tests (nicolas-grekas)

This PR was merged into the 3.3 branch.

Discussion
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Fix AutowiringTypesTest transient tests

| Q             | A
| ------------- | ---
| Branch?       | 3.3
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

In 3.3, we have a race condition because FrameworkBundle and SecurityBundle use the same test folder for their respective AutowiringTypesTest.

Commits
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408e56e404 Fix AutowiringTypesTest transient tests

Author: fabpot

Tests/Functional/WebTestCase.php

@@ -68,6 +68,6 @@ protected static function createKernel(array $options = array())
 
     protected static function getVarDir()
     {
-        return substr(strrchr(get_called_class(), '\\'), 1);
+        return 'FB'.substr(strrchr(get_called_class(), '\\'), 1);
     }
 }