Add test config to net_test_device

This change allows TradeFederation to run the test directly.
Refer to b/35882476 for design and discussion of this change.

Bug: 35882476
Test: local test
tradefed.sh run template/local --template:map test=net_test_device

Change-Id: Ie3e287aba9cd38cbfceef36885c863ba2d34b31a
diff --git a/device/Android.bp b/device/Android.bp
index 314dd50..4dedf03 100644
--- a/device/Android.bp
+++ b/device/Android.bp
@@ -26,6 +26,7 @@
 // ========================================================
 cc_test {
     name: "net_test_device",
+    test_suites: ["device-tests"],
     defaults: ["fluoride_defaults"],
     include_dirs: ["system/bt"],
     srcs: [