[promises] Move CreateResolvingFunctions to c++

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index 7711c32ae566640824c95db7f9237bf3412a18c8..dbe0342b93a893ded9dd75b7f34fffe560551f08 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -310,6 +310,10 @@ class V8_EXPORT_PRIVATE Factory final {
   Handle<Context> NewBlockContext(Handle<JSFunction> function,
                                   Handle<Context> previous,
                                   Handle<ScopeInfo> scope_info);
+  // Create a promise context.
+  Handle<Context> NewPromiseResolvingFunctionContext(
+      Handle<JSFunction> function, Handle<Cell> already_visited,
+      Handle<JSObject> promise, Handle<Object> debug_event);
 
   // Allocate a new struct.  The struct is pretenured (allocated directly in
   // the old generation).