[autotest] Add a dummy test for testbed.

This change also updates the special task control segments to support testbed.

BUG=chromium:574173
TEST=local run the dummy test.

Change-Id: I233511fa340050b74df3fdbcc76c4a408ded5fcf
Reviewed-on: https://chromium-review.googlesource.com/320204
Commit-Ready: Dan Shi <[email protected]>
Tested-by: Dan Shi <[email protected]>
Reviewed-by: Simran Basi <[email protected]>
diff --git a/server/test.py b/server/test.py
index a46b472..6af056b 100644
--- a/server/test.py
+++ b/server/test.py
@@ -97,7 +97,8 @@
     def _install(self):
         if not self.host:
             from autotest_lib.server import hosts, autotest
-            self.host = hosts.create_host(self.job.machine_dict_list[0])
+            self.host = hosts.create_target_machine(
+                    self.job.machine_dict_list[0])
             # TODO(kevcheng): remove when host client install is supported for
             # ADBHost. crbug.com/543702
             if not self.host.is_client_install_supported: