Fix zero_termination tests in the bots (fixes #27066)

tests/compiler/dart2js/zero_termination_test.dart

 // Copyright (c) 2015, 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.
 
 // A regression test for issue 22667.
 //
 // Makes sure that we don't print a '\0' character for files that are not
 // properly new-line terminated.
 library zero_termination_test;
 
@@ skipping 29 matching lines @@
 }
 
 void cleanup() {
   File outFile = new File(outFilePath);
   if (outFile.existsSync()) {
     outFile.deleteSync();
   }
 }
 
 Future launchDart2Js(args) {
-  String ext = Platform.isWindows ? '.bat' : '';
-  String command =
-      path.normalize(path.join(path.fromUri(Platform.script),
-                    '../../../../sdk/bin/dart2js${ext}'));
-  return Process.run(command, args, stdoutEncoding: null);
+  String executable = Platform.executable;
+  String command = path.join(path.dirname(executable), 'dart2js');
+  String dart2jsPath = path.normalize(

[Bill Hesse, 2016/08/12 19:01:31]

Maybe check if this exists, and don't fail if it is missing?

But I'm happy with changing tests so they only work when run from an SDK, not
from executables and scripts all over the checkout.

[Siggi Cherem (dart-lang), 2016/08/12 20:21:14]

I'd be afraid that the test would be "passing" but not running in that case.

+      path.join(path.fromUri(Platform.script),
+        '../../../../pkg/compiler/lib/src/dart2js.dart'));
+  List allArgs = ['--package-root=${Platform.packageRoot}',

[Bill Hesse, 2016/08/12 19:01:31]

I'm just working on removing packageRoot from test scripts today.  These will
soon be run with a package spec file, not a package root.

[Siggi Cherem (dart-lang), 2016/08/12 20:21:14]

good point - we should fix it to pass along whichever was specified in the first
place.

+       dart2jsPath]..addAll(args);
+  return Process.run(Platform.executable, allArgs, stdoutEncoding: null);
 }
 
 void check(ProcessResult result) {
   Expect.notEquals(0, result.exitCode);
   List<int> stdout = result.stdout;
   String stdoutString = UTF8.decode(stdout);
   Expect.isTrue(stdoutString.contains("Error"));
   // Make sure the "499" from the last line is in the output.
   Expect.isTrue(stdoutString.contains("499"));
 
@@ skipping 40 matching lines @@
     await testHttp();
   } finally {
     await tempDir.delete(recursive:true);
   }
 }
 
 main() {
   asyncStart();
   runTests().whenComplete(asyncEnd);
 }