Generate the proper error when a constant refers to itself.

pkg/analyzer/test/src/task/dart_test.dart

Index: pkg/analyzer/test/src/task/dart_test.dart
diff --git a/pkg/analyzer/test/src/task/dart_test.dart b/pkg/analyzer/test/src/task/dart_test.dart
index a7e582b1271ac4160ca0a5b6e1245ffd8a995966..aff479b2bdedd620a4b9555893a8e22cd310e197 100644
--- a/pkg/analyzer/test/src/task/dart_test.dart
+++ b/pkg/analyzer/test/src/task/dart_test.dart
@@ -1312,11 +1312,6 @@ class ComputeConstantValueTaskTest extends _AbstractDartTaskTest {
     return null;
   }
 
-  fail_circular_reference_one_element() {
-    // See dartbug.com/23490.
-    _checkCircularities('x', [], 'const x = x;');
-  }
-
   test_annotation_with_args() {
     Source source = newSource('/test.dart', '''
 const x = 1;
@@ -1369,6 +1364,11 @@ const y = x + 1;
 ''');
   }
 
+  test_circular_reference_one_element() {
+    // See dartbug.com/23490.
+    _checkCircularities('x', [], 'const x = x;');
+  }
+
   test_circular_reference_strongly_connected_component() {
     // When there is a circularity, all elements in the strongly connected
     // component should be marked as having an error.