WIP [esnext] implement async iteration proposal

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index d93552b2a9d50eabd5a4760ea6109c91bcc7f9e5..4ec20991501cc3a6701be576dc3ddeb6ba3d65cb 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -951,12 +951,19 @@ void MacroAssembler::AssertBoundFunction(Register object) {
 
 void MacroAssembler::AssertGeneratorObject(Register object) {
   if (emit_debug_code()) {
+    Label ok;
     test(object, Immediate(kSmiTagMask));
     Check(not_equal, kOperandIsASmiAndNotAGeneratorObject);
     Push(object);
     CmpObjectType(object, JS_GENERATOR_OBJECT_TYPE, object);
     Pop(object);
+    j(equal, &ok);
+
+    Push(object);
+    CmpObjectType(object, JS_ASYNC_GENERATOR_OBJECT_TYPE, object);
+    Pop(object);
     Check(equal, kOperandIsNotAGeneratorObject);
+    bind(&ok);
   }
 }