Get rid of the different kinds of yield in the AST & full-codegen.

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index b99d9852d19f82974333fe74ff9b7f3fa0def7b8..1ecc43e500c141fdda83fae9c1b4a6b45af8214f 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -494,7 +494,6 @@ class PreParserFactory {
   }
   PreParserExpression NewYield(PreParserExpression generator_object,
                                PreParserExpression expression,
-                               Yield::Kind yield_kind,
                                int pos) {
     return PreParserExpression::Default();
   }
@@ -708,6 +707,10 @@ class PreParserTraits {
     return PreParserExpression::Default();
   }
 
+  PreParserExpression BuildIteratorResult(PreParserExpression value,
+                                          bool done) {
+    return PreParserExpression::Default();
+  }
   PreParserExpression NewThrowReferenceError(MessageTemplate::Template message,
                                              int pos) {
     return PreParserExpression::Default();
@@ -1138,8 +1141,7 @@ ZoneList<PreParserExpression>* PreParserTraits::GetNonPatternList() const {
 
 PreParserExpression PreParserTraits::RewriteYieldStar(
     PreParserExpression generator, PreParserExpression expression, int pos) {
-  return pre_parser_->factory()->NewYield(
-      generator, expression, Yield::kDelegating, pos);
+  return PreParserExpression::Default();
 }
 
 PreParserExpression PreParserTraits::RewriteInstanceof(PreParserExpression lhs,