PHPUnit HelperTest fix error 4096

Commit 5458f70 changed function
helper_array_transpose() signature, the argument MUST be an array so it
does not make sense for the unit test to cover NULL, Scalar and Object
types.

tests/Mantis/HelperTest.php

@@ -53,15 +53,6 @@ public function testArrayTranspose( $p_in, $p_out ) {
 	 */
 	public function providerArrayTranspose() {
 		return array(
-			# null
-			array( null, null ),
-
-			# scalar
-			array( 123, 123 ),
-
-			# object
-			array( $this, $this ),
-
 			# simple array
 			array( array(123,456), array(123,456) ),