Description:
------------
It is possible to call a class function directly dispite that it doesnt have the static keyword.

Reproduce code:
---------------
<?php

class Test
{

function MyFunction()
{
  echo 'Hello';
}

}

Test::MyFunction();

?>

Expected result:
----------------
Should only be possible if the function have been defined with the static keyword.
<?php

class Test
{

static function MyFunction()
{
  echo 'Hello';
}

}

Test::MyFunction();

?>

Actual result:
--------------
The code works (it shouldnt).