WIP [esnext] implement async iteration proposal

src/compiler/types.cc

Index: src/compiler/types.cc
diff --git a/src/compiler/types.cc b/src/compiler/types.cc
index a2af190d9d356af94459baffcaae15e10c7f1cde..d18d32aa644e7978f1071a6bdf061e35646bafac 100644
--- a/src/compiler/types.cc
+++ b/src/compiler/types.cc
@@ -214,6 +214,8 @@ Type::bitset BitsetType::Lub(i::Map* map) {
     case JS_DATE_TYPE:
     case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
     case JS_GENERATOR_OBJECT_TYPE:
+    case JS_ASYNC_GENERATOR_OBJECT_TYPE:
+    case JS_ASYNC_FROM_SYNC_ITERATOR_TYPE:
     case JS_MODULE_NAMESPACE_TYPE:
     case JS_ARRAY_BUFFER_TYPE:
     case JS_ARRAY_TYPE:
@@ -318,6 +320,7 @@ Type::bitset BitsetType::Lub(i::Map* map) {
     case BOX_TYPE:
     case PROMISE_RESOLVE_THENABLE_JOB_INFO_TYPE:
     case PROMISE_REACTION_JOB_INFO_TYPE:
+    case ASYNC_GENERATOR_REQUEST_TYPE:
     case DEBUG_INFO_TYPE:
     case BREAK_POINT_INFO_TYPE:
     case CELL_TYPE: