Fix issue 4361 by checking in the resolver if the getter/setter exists.

tests/language/getter_no_setter2_test.dart

Index: tests/language/getter_no_setter2_test.dart
===================================================================
--- tests/language/getter_no_setter2_test.dart	(revision 11766)
+++ tests/language/getter_no_setter2_test.dart	(working copy)
@@ -10,7 +10,7 @@
     {
       bool flag_exception = false;
       try {
-        nextVar = 1;  // Equivalent to this.nextVar = 1.
+        nextVar++;
       } catch (excpt) {
         flag_exception = true;
       }
@@ -19,7 +19,7 @@
     {
       bool flag_exception = false;
       try {
-        this.nextVar = 1;  /// 00: static type warning
+        this.nextVar++;  /// 00: static type warning
       } catch (excpt) {
         flag_exception = true;
       }
@@ -27,8 +27,8 @@
     }
   }
   static test() {
-    nextVar = 0;  /// 01: compile-time error
-    this.nextVar = 0;  /// 02: compile-time error
+    nextVar++;  /// 01: compile-time error
+    this.nextVar++;  /// 02: compile-time error
   }
 }