Extend device with sleep functionality

This changeset adds the ability to sleep on the device via a
device.sleep() method. This invokes sleep on the target device. This
is useful for situations where the passage of time on the target
device does not match that of the host, e.g., gem5.

This changeset also updates a number of workloads to use this new
sleep method.

wlauto/workloads/glbcorp/__init__.py

@@ -18,7 +18,6 @@
 from __future__ import division
 import os
 import re
-import time
 import select
 import json
 import threading
@@ -122,7 +121,7 @@ class GlbCorp(ApkWorkload):
                 raise WorkloadError(result)
             else:
                 self.logger.debug(result)
-            time.sleep(DELAY)
+            self.device.sleep(DELAY)
             self.monitor.wait_for_run_end(self.run_timeout)
 
     def update_result(self, context):  # NOQA
@@ -209,7 +208,7 @@ class GlbRunMonitor(threading.Thread):
         proc = subprocess.Popen(self.command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         while not self.stop_event.is_set():
             if self.run_ended.is_set():
-                time.sleep(DELAY)
+                self.device.sleep(DELAY)
             else:
                 ready, _, _ = select.select([proc.stdout, proc.stderr], [], [], 2)
                 if ready: