[DBAL-2546] Fixed the failure of...

[DBAL-2546] Fixed the failure of `Functional\StatementTest::testIncompletelyFetchedStatementDoesNotBlockConnection()` on pdo_mysql + libmysql

The test case being fixed should reset shared connection during teardown as one if its methods modifies connection attributes.

tests/Doctrine/Tests/DBAL/Functional/Driver/PDOConnectionTest.php

@@ -29,6 +29,13 @@ class PDOConnectionTest extends DbalFunctionalTestCase
         }
     }
 
+    protected function tearDown()
+    {
+        $this->resetSharedConn();
+
+        parent::tearDown();
+    }
+
     public function testDoesNotRequireQueryForServerVersion()
     {
         $this->assertFalse($this->driverConnection->requiresQueryForServerVersion());