Implement handling of arrow functions in the parser

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index c508b4a644fb2540caf3c178d11af3ab7841a057..aac86f9248f028849297fd699454013880c4b8c0 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -2940,6 +2940,14 @@ RUNTIME_FUNCTION(Runtime_FunctionIsGenerator) {
 }
 
 
+RUNTIME_FUNCTION(Runtime_FunctionIsArrow) {
+  SealHandleScope shs(isolate);
+  ASSERT(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->shared()->is_arrow());
+}
+
+
 RUNTIME_FUNCTION(Runtime_FunctionRemovePrototype) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 1);