WIP [esnext] implement async iteration proposal

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index fa238742d5d4f16f68f0816c850f58cc275b284a..23ec09be9fe8d5534e2db5cadc41285023641d52 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -8434,8 +8434,8 @@ class Internals {
   static const int kNodeIsIndependentShift = 3;
   static const int kNodeIsActiveShift = 4;
 
-  static const int kJSApiObjectType = 0xbb;
-  static const int kJSObjectType = 0xbc;
+  static const int kJSApiObjectType = 0xbc;
+  static const int kJSObjectType = 0xbd;
   static const int kFirstNonstringType = 0x80;
   static const int kOddballType = 0x83;
   static const int kForeignType = 0x87;