Remove the unit test for namespaced functions.

That particular test caused the unit tests to fail on PHP 5.2 and it was only included to ensure that the sniff would *not* run on namespaced functions.

WordPress/Tests/DB/RestrictedFunctionsUnitTest.inc

@@ -14,7 +14,7 @@ class Bar {
 $x = new Foo();
 $x->mysql_info(); // ok
 $y = Bar::mysql_info(); // ok
-\SomeNamespace\mysql_info(); // ok
+prefix_mysql_info(); // ok
 
 
 /**