[async-iteration] implement Async-from-Sync Iterator

src/builtins/builtins.h

Index: src/builtins/builtins.h
diff --git a/src/builtins/builtins.h b/src/builtins/builtins.h
index 5673ce21e0901bff74b36a0c7400e7a7d813a199..80adbabcf41b8940d915e5c8559d35532d75fff6 100644
--- a/src/builtins/builtins.h
+++ b/src/builtins/builtins.h
@@ -785,7 +785,18 @@ namespace internal {
   /* ES6 #sec-%typedarray%.prototype.keys */                                   \
   TFJ(TypedArrayPrototypeKeys, 0)                                              \
   /* ES6 #sec-%typedarray%.prototype.values */                                 \
-  TFJ(TypedArrayPrototypeValues, 0)
+  TFJ(TypedArrayPrototypeValues, 0)                                            \
+                                                                               \
+  /* Async-from-Sync Iterator builtins */                                      \
+                                                                               \
+  /* %AsyncFromSyncIteratorPrototype% */                                       \
+  /* (proposal-async-iteration/#sec-%asyncfromsynciteratorprototype%-object)*/ \
+  TFJ(AsyncFromSyncIteratorPrototypeNext, 1)                                   \
+  TFJ(AsyncFromSyncIteratorPrototypeThrow, 1)                                  \
+  TFJ(AsyncFromSyncIteratorPrototypeReturn, 1)                                 \
+                                                                               \
+  /* proposal-async-iteration/#sec-async-iterator-value-unwrap-functions */    \
+  TFJ(AsyncIteratorValueUnwrap, 1)
 
 #define IGNORE_BUILTIN(...)