Revert "Issue #2867700 by erozqba, mondrake, mradcliffe, cilefen:...

Revert "Issue #2867700 by erozqba, mondrake, mradcliffe, cilefen: ConnectionUnitTest::testConnectionOpen fails if the driver is not implementing a PDO connection"

This reverts commit 725356f0.

core/tests/Drupal/KernelTests/Core/Database/ConnectionUnitTest.php

@@ -233,12 +233,6 @@ public function testConnectionOpen() {
     $reflection = new \ReflectionObject($connection);
     $connection_property = $reflection->getProperty('connection');
     $connection_property->setAccessible(TRUE);
-    // Skip this test when a database driver does not implement PDO.
-    // An alternative database driver that does not implement PDO
-    // should implement its own connection test."
-    if (get_class($connection_property->getValue($connection)) !== 'PDO') {
-      $this->markTestSkipped('Ignored PDO connection unit test for this driver because it does not implement PDO.');
-    }
     $error_mode = $connection_property->getValue($connection)
       ->getAttribute(\PDO::ATTR_ERRMODE);
     $this->assertEqual($error_mode, \PDO::ERRMODE_SILENT, 'Ensure PDO connection options can be overridden.');