Use run_vm_tests.host to list VM tests if possible

tools/bots/cross-vm.py

Index: tools/bots/cross-vm.py
diff --git a/tools/bots/cross-vm.py b/tools/bots/cross-vm.py
index 54d43c196b325a076b4aa6a88e0d58ae8a2bbb90..3671f20c09a224a4ae2e88deea934b9e7095d635 100644
--- a/tools/bots/cross-vm.py
+++ b/tools/bots/cross-vm.py
@@ -50,14 +50,18 @@ def cross_compiling_builder(arch, mode):
     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)