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

test/cctest/test-ast-expression-visitor.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast/ast.h"
 #include "src/ast/ast-expression-visitor.h"
@@ skipping 360 matching lines @@
   CHECK_TYPES_BEGIN {
     CHECK_EXPR(FunctionLiteral, Bounds::Unbounded()) {
       // Implicit initial yield
       CHECK_EXPR(Yield, Bounds::Unbounded()) {
         CHECK_VAR(.generator_object, Bounds::Unbounded());
         CHECK_EXPR(Assignment, Bounds::Unbounded()) {
           CHECK_VAR(.generator_object, Bounds::Unbounded());
           CHECK_EXPR(CallRuntime, Bounds::Unbounded());
         }
       }
-      // Explicit yield
+      // Explicit yield (argument wrapped with CreateIterResultObject)
       CHECK_EXPR(Yield, Bounds::Unbounded()) {
         CHECK_VAR(.generator_object, Bounds::Unbounded());
+        CHECK_EXPR(CallRuntime, Bounds::Unbounded()) {
+          CHECK_EXPR(Literal, Bounds::Unbounded());
+          CHECK_EXPR(Literal, Bounds::Unbounded());
+        }
+      }
+      // Argument to implicit final return
+      CHECK_EXPR(CallRuntime, Bounds::Unbounded()) {  // CreateIterResultObject
         CHECK_EXPR(Literal, Bounds::Unbounded());
-      }
-      // Implicit final yield
-      CHECK_EXPR(Yield, Bounds::Unbounded()) {
-        CHECK_VAR(.generator_object, Bounds::Unbounded());
         CHECK_EXPR(Literal, Bounds::Unbounded());
       }
       // Implicit finally clause
       CHECK_EXPR(CallRuntime, Bounds::Unbounded()) {
         CHECK_VAR(.generator_object, Bounds::Unbounded());
       }
     }
   }
   CHECK_TYPES_END
 }
@@ skipping 12 matching lines @@
     CHECK_EXPR(FunctionLiteral, Bounds::Unbounded()) {
       CHECK_EXPR(BinaryOperation, Bounds::Unbounded()) {
         // Skip x + x
         CHECK_SKIP();
         CHECK_EXPR(Literal, Bounds::Unbounded());
       }
     }
   }
   CHECK_TYPES_END
 }