Add debug names to scopes.

pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart

Index: pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart b/pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart
index 3af2756416a417f509542bbe7b075f516a13ca6b..6fc434555e455e0826837d8a23444b615a3f20fd 100644
--- a/pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart
@@ -30,8 +30,8 @@ class DillClassBuilder extends KernelClassBuilder {
             null,
             null,
             new Scope(<String, MemberBuilder>{}, <String, MemberBuilder>{},
-                parent.scope, isModifiable: false),
-            new Scope(<String, MemberBuilder>{}, null, null,
+                parent.scope, "class ${cls.name}", isModifiable: false),
+            new Scope(<String, MemberBuilder>{}, null, null, "constructors",
                 isModifiable: false),
             parent,
             cls.fileOffset);