Implement yield* (delegating yield)

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index 33b5fab3fc8c6b9cd198a99384fe4bf60111d738..35f2323d77572b13af7f568058baff33d3a77c6f 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3113,7 +3113,12 @@ Expression* Parser::ParseYieldExpression(bool* ok) {
   Expression* generator_object = factory()->NewVariableProxy(
       current_function_state_->generator_object_variable());
   Expression* expression = ParseAssignmentExpression(false, CHECK_OK);
-  return factory()->NewYield(generator_object, expression, kind, position);
+  Yield* yield =
+      factory()->NewYield(generator_object, expression, kind, position);
+  if (kind == Yield::DELEGATING) {
+    yield->set_index(current_function_state_->NextHandlerIndex());
+  }
+  return yield;
 }