[parser] improve inferred function names for async arrow functions

src/parsing/func-name-inferrer.cc

Index: src/parsing/func-name-inferrer.cc
diff --git a/src/parsing/func-name-inferrer.cc b/src/parsing/func-name-inferrer.cc
index 12013afd282bec18a947c21a167b9b9f0452ac27..0821be0a68a623012df807fb948990a1b38ca5d9 100644
--- a/src/parsing/func-name-inferrer.cc
+++ b/src/parsing/func-name-inferrer.cc
@@ -44,6 +44,11 @@ void FuncNameInferrer::PushVariableName(const AstRawString* name) {
   }
 }
 
+void FuncNameInferrer::RemoveAsyncKeywordFromEnd() {
+  DCHECK(names_stack_.length() > 0);
+  DCHECK(names_stack_.last().name->IsOneByteEqualTo("async"));
+  names_stack_.RemoveLast();
+}
 
 const AstString* FuncNameInferrer::MakeNameFromStack() {
   return MakeNameFromStackHelper(0, ast_value_factory_->empty_string());