Issue 21419. Don't create navigation region for elements without location.

pkg/analysis_server/test/analysis/notification_navigation_test.dart

Index: pkg/analysis_server/test/analysis/notification_navigation_test.dart
diff --git a/pkg/analysis_server/test/analysis/notification_navigation_test.dart b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
index 386c0ff13397ffef0d11b4b3c25c941dfdfa723e..42c2d5a3776dd49734ad47014c58034f2ab005f7 100644
--- a/pkg/analysis_server/test/analysis/notification_navigation_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
@@ -369,6 +369,21 @@ main() {
     });
   }
 
+  test_multiplyDefinedElement() {
+    addFile('$projectPath/bin/libA.dart', 'library A; int TEST = 1;');
+    addFile('$projectPath/bin/libB.dart', 'library B; int TEST = 2;');
+    addTestFile('''
+import 'libA.dart';
+import 'libB.dart';
+main() {
+  TEST;
+}
+''');
+    return prepareNavigation().then((_) {
+      assertNoRegionAt('TEST');
+    });
+  }
+
   test_operator_arithmetic() {
     addTestFile('''
 class A {