fix tests (Type.getInstanceFields order is undefined)

tests/unit/src/unit/issues/Issue6147.hx

@@ -13,7 +13,10 @@ private class B extends A {
 class Issue6147 extends unit.Test {
 	function test() {
 		aeq(['a'], Type.getInstanceFields(A));
-		aeq(['a','b'], Type.getInstanceFields(B));
+		var v = Type.getInstanceFields(B);
+		eq(2, v.length);
+		t(v.indexOf("a") != -1);
+		t(v.indexOf("b") != -1);
 		aeq(['a'], Type.getInstanceFields(A));
 	}
 }