Fix another corner-case behavior of Object::SetSuperProperty.

test/mjsunit/harmony/reflect.js

Index: test/mjsunit/harmony/reflect.js
diff --git a/test/mjsunit/harmony/reflect.js b/test/mjsunit/harmony/reflect.js
index 439c38f0b5c122325aa33b0cbdf2db729f961a76..a3d44b891656d94ee55ea5c334ec2c782c0ab72b 100644
--- a/test/mjsunit/harmony/reflect.js
+++ b/test/mjsunit/harmony/reflect.js
@@ -244,8 +244,7 @@ function prepare(target) {
     assertFalse("nowrite" in receiver);
 
     // Data vs Non-Writable
-    // TODO(neis): This must return false but currently doesn't.
-    // assertFalse(Reflect.set({}, "nowrite", value, target));
+    assertFalse(Reflect.set({}, "nowrite", value, target));
 
     // Data vs Accessor
     assertFalse(Reflect.set({}, "unknown", 0, {set unknown(x) {}}));
@@ -264,6 +263,14 @@ function prepare(target) {
     // Accessor vs Non-Object
     assertTrue(Reflect.set(target, "setter2", value, null));
     assertFalse(Reflect.set(target, "getter", value, null));
+
+    let receiver2 = {};
+    Object.defineProperty(receiver2, "bla",
+        {configurable: false, writable: true, value: true});
+    Object.defineProperty(receiver2, "not_in_target",
+        {configurable: false, writable: true, value: true});
+    assertTrue(Reflect.set(target, "bla", value, receiver2));
+    assertTrue(Reflect.set(target, "not_in_target", value, receiver2));
   }
 })();