Terminate user defined database connections after rollback during tes…

…ting while using the DatabaseTransactions trait. (#20340)

src/Illuminate/Foundation/Testing/DatabaseTransactions.php

@@ -19,7 +19,10 @@ public function beginDatabaseTransaction()
 
         $this->beforeApplicationDestroyed(function () use ($database) {
             foreach ($this->connectionsToTransact() as $name) {
-                $database->connection($name)->rollBack();
+                $connection = $database->connection($name);
+
+                $connection->rollBack();
+                $connection->disconnect();
             }
         });
     }