Drop support for older Barback versions.

test/serve/supports_user_defined_lazy_transformers_test.dart

Index: test/serve/supports_user_defined_lazy_transformers_test.dart
diff --git a/test/serve/supports_user_defined_lazy_transformers_test.dart b/test/serve/supports_user_defined_lazy_transformers_test.dart
index c1104e8ed99b5e43f98a0d7c456e1bc2289af1f4..a3ec33f5d8292a85f5273c504694f8402b3c9307 100644
--- a/test/serve/supports_user_defined_lazy_transformers_test.dart
+++ b/test/serve/supports_user_defined_lazy_transformers_test.dart
@@ -9,32 +9,30 @@ import '../test_pub.dart';
 import 'utils.dart';
 
 main() {
-  withBarbackVersions("any", () {
-    integration("supports a user-defined lazy transformer", () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
-        }),
-        d.dir("lib", [d.dir("src", [
-          d.file("transformer.dart", LAZY_TRANSFORMER)
-        ])]),
-        d.dir("web", [
-          d.file("foo.txt", "foo")
-        ])
-      ]).create();
+  integration("supports a user-defined lazy transformer", () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "transformers": ["myapp/src/transformer"]
+      }),
+      d.dir("lib", [d.dir("src", [
+        d.file("transformer.dart", LAZY_TRANSFORMER)
+      ])]),
+      d.dir("web", [
+        d.file("foo.txt", "foo")
+      ])
+    ]).create();
 
-      createLockFile('myapp', pkg: ['barback']);
+    createLockFile('myapp', pkg: ['barback']);
 
-      var server = pubServe();
-      // The build should complete without the transformer logging anything.
-      server.stdout.expect('Build completed successfully');
+    var server = pubServe();
+    // The build should complete without the transformer logging anything.
+    server.stdout.expect('Build completed successfully');
 
-      requestShouldSucceed("foo.out", "foo.out");
-      server.stdout.expect(emitsLines(
-          '[Info from LazyRewrite]:\n'
-          'Rewriting myapp|web/foo.txt.'));
-      endPubServe();
-    });
+    requestShouldSucceed("foo.out", "foo.out");
+    server.stdout.expect(emitsLines(
+        '[Info from LazyRewrite]:\n'
+        'Rewriting myapp|web/foo.txt.'));
+    endPubServe();
   });
 }