[Proxies] Support constructable proxy as new.target

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 7f373e6fc7d1d1b237a0d1eac22a0a584f9a94bf..f46f70b778fc57918ca1d74c2932f127f62679da 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1800,6 +1800,8 @@ class JSReceiver: public HeapObject {
   MUST_USE_RESULT static MaybeHandle<Object> OrdinaryToPrimitive(
       Handle<JSReceiver> receiver, OrdinaryToPrimitiveHint hint);
 
+  static MaybeHandle<Context> GetFunctionRealm(Handle<JSReceiver> receiver);
+
   // Implementation of [[HasProperty]], ECMA-262 5th edition, section 8.12.6.
   MUST_USE_RESULT static Maybe<bool> HasProperty(LookupIterator* it);
   MUST_USE_RESULT static inline Maybe<bool> HasProperty(
@@ -1955,6 +1957,8 @@ class JSObject: public JSReceiver {
   // Gets global object properties.
   inline GlobalDictionary* global_dictionary();
 
+  static MaybeHandle<Context> GetFunctionRealm(Handle<JSObject> object);
+
   // [elements]: The elements (properties with names that are integers).
   //
   // Elements can be in two general modes: fast and slow. Each mode
@@ -7208,6 +7212,8 @@ class JSFunction: public JSObject {
   inline JSObject* global_proxy();
   inline Context* native_context();
 
+  static MaybeHandle<Context> GetFunctionRealm(Handle<JSFunction> function);
+
   // [code]: The generated code object for this function.  Executed
   // when the function is invoked, e.g. foo() or new foo(). See
   // [[Call]] and [[Construct]] description in ECMA-262, section
@@ -9502,6 +9508,8 @@ class JSProxy: public JSReceiver {
   // [hash]: The hash code property (undefined if not initialized yet).
   DECL_ACCESSORS(hash, Object)
 
+  static MaybeHandle<Context> GetFunctionRealm(Handle<JSProxy> proxy);
+
   inline bool has_handler();
 
   DECLARE_CAST(JSProxy)