Remove faulty KNOWN_ORDER from set test

Author: nicolaiparlog

src/test/java/org/codefx/libfx/collection/transform/OptionalTransformingSetTest.java

@@ -40,7 +40,6 @@ private static Feature<?>[] features() {
 				CollectionSize.ANY,
 				// exclude 'CollectionFeature.ALLOWS_NULL_VALUES' because nulls are handled in a special way
 				CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION,
-				CollectionFeature.KNOWN_ORDER,
 				CollectionFeature.SUPPORTS_ADD,
 				CollectionFeature.SUPPORTS_ITERATOR_REMOVE,
 				CollectionFeature.SUPPORTS_REMOVE,