Move the status file parser into its own package.

pkg/status_file/test/repo_status_files_test.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS 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.
+
+/// Tests that every .status file in the Dart repository can be successfully
+/// parsed.
+import 'dart:io';
+
+import 'package:expect/expect.dart';
+import 'package:path/path.dart' as p;
+import 'package:status_file/status_file.dart';
+
+final repoRoot =
+    p.normalize(p.join(p.dirname(p.fromUri(Platform.script)), "../../../"));
+
+void main() {
+  // Parse every status file in the repository.
+  for (var directory in ["tests", p.join("runtime", "tests")]) {
+    for (var entry in new Directory(p.join(repoRoot, directory))
+        .listSync(recursive: true)) {
+      if (!entry.path.endsWith(".status")) continue;
+
+      // Inside the co19 repository, there is a status file that doesn't appear
+      // to be valid and looks more like some kind of template or help document.
+      // Ignore it.
+      if (entry.path.endsWith(p.join("co19", "src", "co19.status"))) continue;
+
+      try {
+        new StatusFile.read(entry.path);
+      } catch (err) {
+        var path = p.relative(entry.path, from: repoRoot);
+        Expect.fail("Could not parse '$path'.\n$err");
+      }
+    }
+  }
+}