Implement set trap for proxies, and revamp class hierarchy in preparation

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 92fa840316a0a372159db9614690844437d38968..3405edc8a768cbd83a12f5d0a998faabf1f74d43 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -3723,8 +3723,7 @@ MaybeObject* Runtime::GetObjectProperty(Isolate* isolate,
   if (name->AsArrayIndex(&index)) {
     return GetElementOrCharAt(isolate, object, index);
   } else {
-    PropertyAttributes attr;
-    return object->GetProperty(*name, &attr);
+    return object->GetProperty(*name);
   }
 }
 
@@ -4636,7 +4635,7 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_Typeof) {
       }
       ASSERT(heap_obj->IsUndefined());
       return isolate->heap()->undefined_symbol();
-    case JS_FUNCTION_TYPE: case JS_REGEXP_TYPE:
+    case JS_FUNCTION_TYPE:
       return isolate->heap()->function_symbol();
     default:
       // For any kind of object not handled above, the spec rule for