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 8a6484ec49132653f5225997c442cd8ffbc352f2..78029503d841bc8e965d293165d52c411e950fc5 100644
--- a/src/compiler/types.cc
+++ b/src/compiler/types.cc
@@ -216,6 +216,8 @@ 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:
@@ -320,6 +322,7 @@ 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: