Convert to androidx.test from android-support-test.

android-support-test has long been deprecated and unsupported,
and it causes problems having both androidx.test and
androiud.support.test included in one binary.

Bug: 172570181
Test: m -j NullHomeTest mediatunertest mediatranscodingtest mediaroutertest mediaframeworktest BluetoothMidiTests
Change-Id: If86f5634beab88db07656f743b19beddd9d77984
diff --git a/tests/NullHomeTest/Android.bp b/tests/NullHomeTest/Android.bp
index 99248bf..fc71d0d 100644
--- a/tests/NullHomeTest/Android.bp
+++ b/tests/NullHomeTest/Android.bp
@@ -17,6 +17,6 @@
     srcs: ["src/**/*.java"],
     certificate: "platform",
     platform_apis: true,
-    static_libs: ["android-support-test"],
+    static_libs: ["androidx.test.rules"],
     test_suites: ["device-tests"],
 }