message: Add asserts to check the IPU wasn't used and to check the IPU compiler was used.
  Test Plan: Used in Sequential patch (But it's a r2.1 feature only)
  Reviewers: #tensorflow, davidn
  Subscribers: romand
diff: @@ -230,6 +230,14 @@ class ReportJSON(object):
  events = self.get_event_trace(session)
  return self.get_events_from_log(events)
  + def assert_no_event(self, msg=""):
  + types, _ = self.get_ipu_events()
  + self.test.assertFalse(types, msg)
  +
  + def assert_compiled_for_ipu(self, msg=""):
  + types, _ = self.get_ipu_events()
  + self.test.assertContainsSubset([IpuTraceEvent.COMPILE_END], types, msg)
  +
  def get_event_trace(self, session=None):
  if self.eager_mode:
  assert session is None, "Sessions can't be used in eager mode"
  