remove invalid non IRI extensions fixture

With the introduction of the IRI class, it is no longer possible to
create extensions without a valid IRI.

Author: xabbuh

data/Extensions/invalid_non_iri.json

@@ -45,9 +45,4 @@ public static function getMultiplePairsExtensions()
     {
         return self::load('multiple_pairs');
     }
-
-    public static function getInvalidNonIriExtensions()
-    {
-        return self::load('invalid_non_iri');
-    }
 }