Add support for tests to declare runtime hints.

bug:21762834
Change-Id: I11f3e6ecb026dcbbb8c73c750c7a70d8a15d81fb
diff --git a/tests/cts/net/AndroidTest.xml b/tests/cts/net/AndroidTest.xml
index 1509256..dc80339 100644
--- a/tests/cts/net/AndroidTest.xml
+++ b/tests/cts/net/AndroidTest.xml
@@ -20,5 +20,6 @@
     </target_preparer>
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
         <option name="package" value="android.net.cts" />
+        <option name="runtime-hint" value="9m4s" />
     </test>
 </configuration>