Description:
------------
When creating the mysqli object, it don't return FALSE as said in the documentation, if the connection failed.

Reproduce code:
---------------
try {
 $this->mysqli = @new mysqli('localhost', 'bad_user', 'password', 'db');
 if ($this->mysqli == FALSE) {
  throw new Exception("Connection failed !");
 }
 var_dump($this->mysqli);
 var_export($this->mysqli);
} catch (Exception $e) {
 $e->showStackTrace();
}

Expected result:
----------------
object(mysqli)#5 (0) { } mysqli::__set_state(array( ))


Actual result:
--------------
Connection failed !