Fix Adapter\Pdo\Mysql::closeConnection on non-default ports

Fixing Magento\Framework\DB\Adapter\Pdo\Mysql::closeConnection when the port is a non-default port.  When we are using a non-default port for the database,  and closeConnection() method is called,  this prevents automatic reconnection from working.  This is because during the connection,  we move the port into $this->_config['port'].

The closeConnection() is not called in normal Magento usage.  However,  it is always called when running the integration tests.  This means that that you cannot use integration tests with a Mysql server on a non-default port.

Steps to reproduce the error that this bugs fixes:

1. Configure a Mysql server using a custom port.
2. Configure Magento integration tests to use this database.
3. Try to run integration tests.

Expected Result:  Integration tests pass.

Actual Result:  Integration tests fail with errors because they use closeConnection() which loses the port configuration.

Author: JacobBrownAustin

lib/internal/Magento/Framework/DB/Adapter/Pdo/Mysql.php

@@ -4030,4 +4030,19 @@ public function getSchemaListener()
         }
         return $this->schemaListener;
     }
+
+    /**
+     * Closes the connection.
+     */
+    public function closeConnection()
+    {
+        /**
+         * _connect() function does not allow port parameter, so put the port back with the host
+         */
+        if (!empty($this->_config['port'])) {
+            $this->_config['host'] = implode(':', [$this->_config['host'], $this->_config['port']]);
+            unset($this->_config['port']);
+        }
+        parent::closeConnection();
+    }
 }