Resynthesize local variables lazily.

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 13cc75e8d94da7a8e9aab279f1a8ffa8d0c5388d..5b6c317619119c7c57e22e72e6915671486a3517 100644
--- a/pkg/analyzer/test/src/summary/resynthesize_test.dart
+++ b/pkg/analyzer/test/src/summary/resynthesize_test.dart
@@ -1033,7 +1033,7 @@ abstract class AbstractResynthesizeTest extends AbstractSingleUnitTest {
         expect(resynthesized.element.type, same(resynthesized));
       }
       expect(resynthesized.typeArguments.length, original.typeArguments.length,
-          reason: desc);
+          reason: '$desc typeArguments.length');
       for (int i = 0; i < resynthesized.typeArguments.length; i++) {
         if (resynthesized.typeArguments[i].isDynamic &&
             original.typeArguments[i] is TypeParameterType) {