[es6] Fix function context check for super and new.target

src/scopes.h

Index: src/scopes.h
diff --git a/src/scopes.h b/src/scopes.h
index f9354188bf31e99858e2da0c0696eb5cd049c9da..e565ff69fe25f7c1197a341a5e96940ced953773 100644
--- a/src/scopes.h
+++ b/src/scopes.h
@@ -483,15 +483,14 @@ class Scope: public ZoneObject {
   // The number of contexts between this and scope; zero if this == scope.
   int ContextChainLength(Scope* scope);
 
-  // Find the script scope.
-  // Used in modules implemenetation to find hosting scope.
-  // TODO(rossberg): is this needed?
-  Scope* ScriptScope();
-
-  // Find the first function, global, or eval scope.  This is the scope
-  // where var declarations will be hoisted to in the implementation.
+  // Find the first function, script, eval or (declaration) block scope. This is
+  // the scope where var declarations will be hoisted to in the implementation.
   Scope* DeclarationScope();
 
+  // Find the first (non-arrow) function or script scope.  This is where
+  // 'this' is bound, and what determines the function kind.
+  Scope* ReceiverScope();
+
   Handle<ScopeInfo> GetScopeInfo(Isolate* isolate);
 
   // Get the chain of nested scopes within this scope for the source statement