Drop support for older Barback versions.

test/dart2js/compiles_generated_file_from_dependency_outside_web_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import '../serve/utils.dart';
 
 main() {
   // This is a regression test for issue #17198.
-  withBarbackVersions("any", () {
-    integration("compiles a Dart file that imports a generated file to JS "
-        "outside web/", () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "version": "0.0.1",
-          "transformers": ["myapp/transformer"]
-        }),
-        d.dir("lib", [
-          d.file("transformer.dart", dartTransformer("munge"))
-        ]),
-        d.dir("test", [
-          d.file("main.dart", """
+  integration("compiles a Dart file that imports a generated file to JS "
+      "outside web/", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "version": "0.0.1",
+        "transformers": ["myapp/transformer"]
+      }),
+      d.dir("lib", [
+        d.file("transformer.dart", dartTransformer("munge"))
+      ]),
+      d.dir("test", [
+        d.file("main.dart", """
 import "other.dart";
 void main() => print(TOKEN);
 """),
-          d.file("other.dart", """
+        d.file("other.dart", """
 library other;
 const TOKEN = "before";
 """)
         ])
-      ]).create();
+    ]).create();
 
-      createLockFile('myapp', pkg: ['barback']);
+    createLockFile('myapp', pkg: ['barback']);
 
-      pubServe(args: ["test"]);
-      requestShouldSucceed("main.dart.js", contains("(before, munge)"),
-          root: "test");
-      endPubServe();
-    });
+    pubServe(args: ["test"]);
+    requestShouldSucceed("main.dart.js", contains("(before, munge)"),
+        root: "test");
+    endPubServe();
   });
 }