Remove workaround for missing setter function returns (dartbug.com/15914).

pkg/analyzer/test/services/data/cu_tests.data

 >>>
 class
 A
 {
 }
 <<<
 class A {
 }
 >>> dartbug.com/15876
 // fisk
@@ skipping 121 matching lines @@
     const y = null;
   }
 
   @NoInline()
   factory X(@NoInline() x) => null;
 
   @NoInline()
   int x() => null;
 }
 >>>
-Object get _globalState => null;
-
-set _globalState(Object val) {
-}
-<<<
-Object get _globalState => null;
-
-set _globalState(Object val) {
-}
->>>
 var x = #foo;
 var y=#foo.bar.baz;
 <<<
 var x = #foo;
 var y = #foo.bar.baz;
 >>>
 class Zounds extends Object native "Zapp" {
 }
 <<<
 class Zounds extends Object native "Zapp" {
@@ skipping 11 matching lines @@
 <<<
 import 'package:sdasdsasadasd/ass/sadasdas/sadasdsad_asdasd_asdsada_adsasdasdsa.dart';
 >>>
 import 'package:sdasdsasadasd/ass/sadasdas/sadasdsad_asdasd_asdsada_adsasdasdsa.dart' as sass;
 <<<
 import 'package:sdasdsasadasd/ass/sadasdas/sadasdsad_asdasd_asdsada_adsasdasdsa.dart'
     as sass;
 >>> dartbug.com/15912
 abstract class ListBase<E> = Object with ListMixin<E>;
 <<<
-abstract class ListBase<E> = Object with ListMixin<E>;
+abstract class ListBase<E> = Object with ListMixin<E>;
+>>> dartbug.com/15914
+Object get _globalState => null;
+
+set _globalState(Object val) {
+}
+
+void setX(x) {
+}
+<<<
+Object get _globalState => null;
+
+set _globalState(Object val) {
+}
+
+void setX(x) {
+}