Delete a TODO task that has been taken care of.

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

Index: pkg/analyzer/test/src/summary/resynthesize_test.dart
diff --git a/pkg/analyzer/test/src/summary/resynthesize_test.dart b/pkg/analyzer/test/src/summary/resynthesize_test.dart
index 9492ca8ad783df31995f60eef0e65920897e68ff..48f35c59465b51256e8e2d56aa984374404c40b9 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_test.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_test.dart
@@ -239,7 +239,9 @@ class ResynthTest extends ResolverTestCase {
             'setter $name');
       }
     }
-    // TODO(paulberry): test metadata and offsetToElementMap.
+    // Note: no need to test CompilationUnitElementImpl._offsetToElementMap
+    // since it is built on demand when needed (see
+    // CompilationUnitElementImpl.getElementAt])
   }
 
   void compareConstAstLists(