Increase NNAPI VTS single-test timeout to 20m.

SaveToCache_TOCTOU/PrepareFromCache_TOCTOU loops 100 times to generate
and reload compilation cache. Some drivers may hit the 60-second
timeout.

Bug: 160197150
Test: Add a test sleeping for 2min to NNAPI 1.2/1.3 VTS
      and run with vts-tradefed
Change-Id: Id232f4954180d8d7a9b91f8d2e4e6f2ee4640ed7
diff --git a/neuralnetworks/1.3/vts/functional/AndroidTest.xml b/neuralnetworks/1.3/vts/functional/AndroidTest.xml
index e5acd90..c418aaa 100644
--- a/neuralnetworks/1.3/vts/functional/AndroidTest.xml
+++ b/neuralnetworks/1.3/vts/functional/AndroidTest.xml
@@ -28,5 +28,6 @@
     <test class="com.android.tradefed.testtype.GTest" >
         <option name="native-test-device-path" value="/data/local/tmp" />
         <option name="module-name" value="VtsHalNeuralnetworksV1_3TargetTest" />
+        <option name="native-test-timeout" value="20m" />
     </test>
 </configuration>