Use checked-in .package file for building and testing

tests/standalone/io/code_collection_test.dart

 // Copyright (c) 2013, 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.
 
 // Dart test program testing code GC.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 
@@ skipping 26 matching lines @@
     bar();
     if (i > 1) {
       timer.cancel();
       // foo is called again to make sure we can still run it even after
       // its code has been detached.
       var ret = foo(2);
     }
   });
 }
 
+List<String> packageOptions() {
+  if (Platform.packageRoot != null) {
+    return <String>['--package-root=${Platform.packageRoot}'];
+  } else if (Platform.packageConfig != null) {
+    return <String>['--packages=${Platform.packageConfig}'];
+  } else {
+    return <String>[];
+  }
+}
 
 main(List<String> arguments) {
   if (arguments.contains("--run")) {
     doTest();
   } else {
     // Run the test and capture stdout.
-    var pr = Process.runSync(Platform.executable,
-        ["--verbose-gc",
+    var args = packageOptions();
+    args.addAll(["--verbose-gc",
          "--collect-code",
          "--code-collection-interval-in-us=0",
          "--old_gen_growth_rate=10",
          "--log-code-drop",
          "--optimization-counter-threshold=-1",
-         "--package-root=${Platform.packageRoot}",
          Platform.script.toFilePath(),
          "--run"]);
+    var pr = Process.runSync(Platform.executable, args);
 
     Expect.equals(0, pr.exitCode);
 
     // Code drops are logged with --log-code-drop. Look through stdout for the
     // message that foo's code was dropped.
     print(pr.stdout);
     var count = 0;
     pr.stdout.split("\n").forEach((line) {
       if (line.contains("foo=2")) {
         Expect.equals(0, count);
         count++;
       }
       if (line.contains("Detaching code") && line.contains("foo")) {
         Expect.equals(1, count);
         count++;
       }
       if (line.contains("foo=3")) {
         Expect.equals(2, count);
         count++;
       }
     });
     Expect.equals(3, count);
   }
 }