Refactor test servers to make them less global.

test/list_package_dirs/lists_dependency_directories_test.dart

Index: test/list_package_dirs/lists_dependency_directories_test.dart
diff --git a/test/list_package_dirs/lists_dependency_directories_test.dart b/test/list_package_dirs/lists_dependency_directories_test.dart
index 2fbcb97404ad7e7174188d1546baf6c8ffda73be..8001ca7889d522c1c78a14b6c06fd341fcacd35a 100644
--- a/test/list_package_dirs/lists_dependency_directories_test.dart
+++ b/test/list_package_dirs/lists_dependency_directories_test.dart
@@ -34,8 +34,9 @@ main() {
         outputJson: {
           "packages": {
             "foo": path.join(sandboxDir, "foo", "lib"),
-            "bar": port.then((p) => path.join(sandboxDir, cachePath, "hosted",
-                "localhost%58$p", "bar-1.0.0", "lib")),
+            "bar": globalServer.port.then(
+                (p) => path.join(sandboxDir, cachePath, "hosted",
+                    "localhost%58$p", "bar-1.0.0", "lib")),
             "myapp": canonicalize(path.join(sandboxDir, appPath, "lib"))
           },
           "input_files": [