Parse arrow functions at proper precedence level

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 8c59ce86c9fe11f4c8ed1cfb76a8ed69cfcd3f2f..ad60de9ca87c5acb350190919e4ad2909ea76192 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -11525,6 +11525,11 @@ void HOptimizedGraphBuilder::HandleLiteralCompareNil(CompareOperation* expr,
 void HOptimizedGraphBuilder::VisitSpread(Spread* expr) { UNREACHABLE(); }
 
 
+void HOptimizedGraphBuilder::VisitEmptyParentheses(EmptyParentheses* expr) {
+  UNREACHABLE();
+}
+
+
 HInstruction* HOptimizedGraphBuilder::BuildThisFunction() {
   // If we share optimized code between different closures, the
   // this-function is not a constant, except inside an inlined body.