minor symfony#17383 Removed a duplicated test in CardSchemeValidatorTest (javiereguiluz)

This PR was merged into the 2.3 branch.

Discussion
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Removed a duplicated test in CardSchemeValidatorTest

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

I was looking into making `CardSchemeValidatorTest` faster. I couldn't make it, but I found a duplicated test.

Commits
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1974131 Removed a duplicated test in CardSchemeValidatorTest

Author: Tobion

src/Symfony/Component/Validator/Tests/Constraints/CardSchemeValidatorTest.php

@@ -92,7 +92,6 @@ public function getValidNumbers()
             array('MAESTRO', '5020507657408074712'),
             array('MAESTRO', '5612559223580173965'),
             array('MAESTRO', '6759744069209'),
-            array('MAESTRO', '6759744069209'),
             array('MAESTRO', '6594371785970435599'),
             array('MASTERCARD', '5555555555554444'),
             array('MASTERCARD', '5105105105105100'),