Remove convertConstructors.

pkg/front_end/test/fasta/rasta/enum.dart.outline.expect

Index: pkg/front_end/test/fasta/rasta/enum.dart.outline.expect
diff --git a/pkg/front_end/test/fasta/rasta/enum.dart.outline.expect b/pkg/front_end/test/fasta/rasta/enum.dart.outline.expect
index b434f604ff2e257d8056b1cc9e68b09fbebcb546..9b3c542f16aa899d99d3b0b8d2cdc8e2eece55de 100644
--- a/pkg/front_end/test/fasta/rasta/enum.dart.outline.expect
+++ b/pkg/front_end/test/fasta/rasta/enum.dart.outline.expect
@@ -10,8 +10,8 @@ class Foo extends core::Object {
   const constructor •(core::int index) → void
     : self::Foo::index = index
     ;
-  constructor •() → void
-    ;
   method toString() → core::String
     return const <core::int, core::String>{0: "Foo.ec1", 1: "Foo.ec2"}.[](this.{=self::Foo::index});
 }
+static method main() → dynamic
+  ;