fix unit test coverage

Author: wangzlei

aws-opentelemetry-distro/tests/amazon/opentelemetry/distro/test_aws_batch_unsampled_span_processor.py

@@ -21,7 +21,6 @@ def test_on_end_sampled(self, mock_span_class):
 
         self.processor.on_start(mock_span)
         self.processor.on_end(mock_span)
-        self.processor.shutdown()
 
         self.assertEqual(len(self.processor.queue), 0)
         mock_span.set_attribute.assert_not_called()
@@ -44,10 +43,10 @@ def test_on_end_not_sampled(self, mock_span_class):
         self.assertEqual(len(self.processor.queue), 1)
         self.assertIn(AWS_TRACE_FLAG_UNSAMPLED, mock_span1.set_attribute.call_args_list[0][0][0])
 
+        self.processor.shutdown()
         mock_span2 = mock_span_class.return_value
         mock_span2.context.trace_flags = trace_flags
         self.processor.on_start(mock_span2)
         self.processor.on_end(mock_span2)
 
-        self.assertEqual(len(self.processor.queue), 1)
-        self.assertIn(AWS_TRACE_FLAG_UNSAMPLED, mock_span2.set_attribute.call_args_list[0][0][0])
+        self.assertEqual(len(self.processor.queue), 0)