Set CtsMediaStress max shard to 2

Setup time is very expensive, ensure we don't shard
too much and multiply it.

Test: none
Change-Id: Idc446da7e0fa527188c5d7c074e2ef69d8b6aecc
(cherry picked from commit 9b29cfa6549d5d246cb1e7afd3486d1e588c5c63)
diff --git a/tests/tests/mediastress/AndroidTest.xml b/tests/tests/mediastress/AndroidTest.xml
index bc39044..6e3678f 100644
--- a/tests/tests/mediastress/AndroidTest.xml
+++ b/tests/tests/mediastress/AndroidTest.xml
@@ -28,6 +28,7 @@
         <option name="package" value="android.mediastress.cts" />
         <!-- test-timeout unit is ms, value = 30 min -->
         <option name="test-timeout" value="1800000" />
+        <option name="ajur-max-shard" value="2" />
         <option name="runtime-hint" value="3h" />
     </test>
 </configuration>