Make servePackages's contents argument saner.

sdk/lib/_internal/pub/test/get/hosted/get_test.dart

Index: sdk/lib/_internal/pub/test/get/hosted/get_test.dart
diff --git a/sdk/lib/_internal/pub/test/get/hosted/get_test.dart b/sdk/lib/_internal/pub/test/get/hosted/get_test.dart
index fa2ffe43ad76b1f922d46c300fc1a6270bd0ce7d..58890c818377599f3a60f623bfa8f7797e6b0057 100644
--- a/sdk/lib/_internal/pub/test/get/hosted/get_test.dart
+++ b/sdk/lib/_internal/pub/test/get/hosted/get_test.dart
@@ -11,7 +11,7 @@ import '../../test_pub.dart';
 main() {
   initConfig();
   integration('gets a package from a pub server', () {
-    servePackages([packageMap("foo", "1.2.3")]);
+    servePackages((builder) => builder.serve("foo", "1.2.3"));
 
     d.appDir({"foo": "1.2.3"}).create();
 
@@ -22,7 +22,7 @@ main() {
   });
 
   integration('URL encodes the package name', () {
-    servePackages([]);
+    serveNoPackages();
 
     d.appDir({"bad name!": "1.2.3"}).create();