Use run_vm_tests.host to list VM tests if possible

tools/bots/cross-vm.py

 #!/usr/bin/python
 # 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.
 
 import os
 import re
 import shutil
 import sys
 
@@ skipping 32 matching lines @@
   (checked_recording, checked_recording_out) = record_names(
       'checked_tests', arch, mode)
 
   temporary_files = [tarball, recording, recording_out, checked_recording,
                      checked_recording_out]
   bot.Clobber()
   try:
     num_run = int(os.environ['BUILDBOT_ANNOTATED_STEPS_RUN'])
     if num_run == 1:
       with bot.BuildStep('Build %s %s' % (arch, mode)):
-        args = [sys.executable, build_py,
-                '-m%s' % mode, '--arch=%s' % arch, 'runtime']
+        run([sys.executable, build_py,
+             '-m%s' % mode, '--arch=%s' % arch, 'runtime'])
+        # We need to build 'run_vm_tests.host' as well to enable
+        # test.py to list the VM tests.
+        run([sys.executable, build_py,
+             '-m%s' % mode, '--arch=%s' % arch, 'run_vm_tests.host'])
 
-        run(args)
       with bot.BuildStep('Create build tarball'):
         run(['tar', '-cjf', tarball, '--exclude=**/obj',
              '--exclude=**/obj.host', '--exclude=**/obj.target',
-             '--exclude=**/*analyzer*', '--exclude=**/*IA32', 'out/'])
+             '--exclude=**/*analyzer*', '--exclude=**/run_vm_tests.host',
+             'out/'])
 
       with bot.BuildStep('Upload build tarball'):
         uri = "%s/%s" % (GCS_BUCKET, tarball)
         run([GSUTIL, 'cp', tarball, uri])
         run([GSUTIL, 'setacl', 'public-read', uri])
 
       with bot.BuildStep('prepare tests'):
         uri = "%s/%s" % (GCS_BUCKET, recording)
         run(test_args + ['--mode=' + mode, '--arch=' + arch,
                          '--record_to_file=' + recording])
@@ skipping 78 matching lines @@
     mode = target_vm_pattern_match.group(2)
     target_builder(arch, mode)
   else:
     raise Exception("Unknown builder name %s" % name)
 
 if __name__ == '__main__':
   try:
     sys.exit(main())
   except OSError as e:
     sys.exit(e.errno)