Fix prelinker when a local name shadows an import prefix.

pkg/analyzer/test/src/summary/summary_common.dart

Index: pkg/analyzer/test/src/summary/summary_common.dart
diff --git a/pkg/analyzer/test/src/summary/summary_common.dart b/pkg/analyzer/test/src/summary/summary_common.dart
index 3c363dfb287657e198a86206df638f8fbc7c6bda..85871dd17beea6da14d4af8239f7054cc34f7868 100644
--- a/pkg/analyzer/test/src/summary/summary_common.dart
+++ b/pkg/analyzer/test/src/summary/summary_common.dart
@@ -8880,6 +8880,11 @@ D d;''');
     checkTypeRef(findVariable('d').type, absUri('/a.dart'), 'a.dart', 'D');
   }
 
+  test_localNameShadowsImportPrefix() {
+    serializeLibraryText('import "dart:async" as a; class a {}; a x;');
+    checkTypeRef(findVariable('x').type, null, null, 'a');
+  }
+
   test_metadata_classDeclaration() {
     checkAnnotationA(
         serializeClassText('const a = null; @a class C {}').annotations);