Revert two Kernel changes that were causing test failures.

tests/language_strong/async_await_syntax_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Test async/await syntax.
 
 import 'dart:async' show Stream;
 
 var yield = 0;
 var await = 0;
@@ skipping 36 matching lines @@
 a05h() async { //                              //# a05h: continued
     yield* st; //                              //# a05h: compile-time error
 } //                                           //# a05h: continued
 a06a() async { await for (var o in st) {} } // //# a06a: ok
 a06b() sync* { await for (var o in st) {} } // //# a06b: compile-time error
 a07a() sync* { yield 0; } //                   //# a07a: ok
 a07b() sync { yield 0; } //                    //# a07b: compile-time error
 a08a() sync* { yield* []; } //                 //# a08a: ok
 a08b() sync { yield 0; } //                    //# a08b: compile-time error
 a09a() async* { yield 0; } //                  //# a09a: ok
-a10a() async* { yield* []; } //                //# a10a: compile-time error
+a10a() async* { yield* []; } //                //# a10a: static type warning
 
 get sync sync {} //                            //# a11a: compile-time error
 get sync sync* {} //                           //# a11b: ok
 get async async {} //                          //# a11c: ok
 get async async* {} //                         //# a11d: ok
 
 get sync {} //                                 //# a12a: ok
 get sync* {} //                                //# a12b: compile-time error
 get async {} //                                //# a12c: ok
 get async* {} //                               //# a12d: compile-time error
@@ skipping 47 matching lines @@
   b02a() async {} //                             //# b02a: ok
   b03a() async* {} //                            //# b03a: ok
   b04a() sync* {} //                             //# b04a: ok
   b04b() sync {} //                              //# b04b: compile-time error
   b05a() async { await 0; } //                   //# b05a: ok
   b06a() async { await for (var o in st) {} } // //# b06a: ok
   b06b() async { await for ( ; ; ) {} } //       //# b06b: compile-time error
   b07a() sync* { yield 0; } //                   //# b07a: ok
   b08a() sync* { yield* []; } //                 //# b08a: ok
   b09a() async* { yield 0; } //                  //# b09a: ok
-  b10a() async* { yield* []; } //                //# b10a: compile-time error
+  b10a() async* { yield* []; } //                //# b10a: static type warning
   b10b() async { yield 0; } //                   //# b10b: compile-time error
 
   get sync sync {} //                            //# b11a: compile-time error
   get sync sync* {} //                           //# b11b: ok
   get async async {} //                          //# b11c: ok
   get async async* {} //                         //# b11d: ok
 
   get sync {} //                                 //# b12a: ok
   get sync* {} //                                //# b12b: compile-time error
   get async {} //                                //# b12c: ok
@@ skipping 24 matching lines @@
   c01c() sync* => null; c01c(); //                       //# c01c: compile-time error
   c02a() async {} c02a(); //                             //# c02a: ok
   c03a() async* {} c03a(); //                            //# c03a: ok
   c04a() sync* {} c04a(); //                             //# c04a: ok
   c04b() sync {} c04b(); //                              //# c04b: compile-time error
   c05a() async { await 0; } c05a(); //                   //# c05a: ok
   c06a() async { await for (var o in st) {} } c06a(); // //# c06a: ok
   c07a() sync* { yield 0; } c07a(); //                   //# c07a: ok
   c08a() sync* { yield* []; } c08a(); //                 //# c08a: ok
   c09a() async* { yield 0; } c09a(); //                  //# c09a: ok
-  c10a() async* { yield* []; } c10a(); //                //# c10a: compile-time error
+  c10a() async* { yield* []; } c10a(); //                //# c10a: static type warning
   c11a() async { yield -5; } c11a(); //                  //# c11a: compile-time error
   c11b() async { yield* st; } c11b(); //                 //# c11b: compile-time error
 }
 
 method2() {
   var d01a = () async => null; d01a(); //                        //# d01a: ok
   var d01b = () async* => null; d01b(); //                       //# d01b: compile-time error
   var d01c = () sync* => null; d01c(); //                        //# d01c: compile-time error
   var d02a = () async {}; d02a(); //                             //# d02a: ok
   var d03a = () async* {}; d03a(); //                            //# d03a: ok
   var d04a = () sync* {}; d04a(); //                             //# d04a: ok
   var d04b = () sync {}; d04b(); //                              //# d04b: compile-time error
   var d05a = () async { await 0; }; d05a(); //                   //# d05a: ok
   var d06a = () async { await for (var o in st) {} }; d06a(); // //# d06a: ok
   var d07a = () sync* { yield 0; }; d07a(); //                   //# d07a: ok
   var d08a = () sync* { yield* []; }; d08a(); //                 //# d08a: ok
-  var d08b = () sync* { yield*0+1; }; d08b(); //                 //# d08b: compile-time error
+  var d08b = () sync* { yield*0+1; }; d08b(); //                 //# d08b: static type warning
   var d08c = () { yield*0+1; }; d08c(); //                       //# d08c: ok
   var d09a = () async* { yield 0; }; d09a(); //                  //# d09a: ok
-  var d10a = () async* { yield* []; }; d10a(); //                //# d10a: compile-time error
+  var d10a = () async* { yield* []; }; d10a(); //                //# d10a: static type warning
 }
 
 void main() {
   var a;
   var c = new C();
   c = new C.e1(); //# e1: continued
   c = new C.e2(); //# e2: continued
   c = new C.e3(); //# e3: continued
   c = new C.e4(); //# e4: continued
   c = new C.e5(); //# e5: continued
@@ skipping 91 matching lines @@
   a = c.async; // //# b14c: continued
   a = c.async; // //# b14d: continued
   c.sync(); //    //# b15a: continued
   c.sync(); //    //# b15b: continued
   c.async(); //   //# b15c: continued
   c.async(); //   //# b15d: continued
 
   method1();
   method2();
 }