Bump num_inference from 10 to 2000

Change-Id: Iad29b917c9d7e9c286f675cf1dc4a2bc67f0cf5a
(cherry picked from commit d2a8fa9eaaafc995325d72afcbb605301fc5d1ef)
diff --git a/tests/multiple_tpus_test.py b/tests/multiple_tpus_test.py
index 63cf602..a4a3b86 100644
--- a/tests/multiple_tpus_test.py
+++ b/tests/multiple_tpus_test.py
@@ -70,7 +70,7 @@
               0.88)
       print('Thread: %d, done detection task' % tid)
 
-    num_inferences = 10
+    num_inferences = 2000
     t1 = threading.Thread(target=classification_task, args=(num_inferences,))
     t2 = threading.Thread(target=detection_task, args=(num_inferences,))