Make selector registration in the resolver and code generator more explicit.

tests/compiler/dart2js/unparser_test.dart

Index: tests/compiler/dart2js/unparser_test.dart
diff --git a/tests/compiler/dart2js/unparser_test.dart b/tests/compiler/dart2js/unparser_test.dart
index 2e6ffe191762b033d33bfc80dff4ba8f6e91a62c..5d8dd80869b7580c8b5bbd674794c5b590624159 100644
--- a/tests/compiler/dart2js/unparser_test.dart
+++ b/tests/compiler/dart2js/unparser_test.dart
@@ -194,7 +194,7 @@ testVariableDefinitions() {
 
 testGetSet() {
   // Top-level get/set.
-  testDart2Dart('get foo(){return 5;}set foo(arg){}main(){foo; foo=5;}');
+  testDart2Dart('set foo(arg){}get foo(){return 5;}main(){foo; foo=5;}');
   // Field get/set.
   testDart2Dart('main(){var a=new A(); a.foo; a.foo=5;}'
       'class A{set foo(a){}get foo(){return 5;}}');