Migrate packages/providers/MediaProvider to androidx.test

See go/jetpack-test-android-migration

Test: make checkbuild
Change-Id: I9fec8fc35b9deec44556ffdb503bea8bfa10ba4c
diff --git a/tests/AndroidTest.xml b/tests/AndroidTest.xml
index a1d075b..d05ca2a 100644
--- a/tests/AndroidTest.xml
+++ b/tests/AndroidTest.xml
@@ -23,7 +23,7 @@
     <option name="test-tag" value="MediaProviderTests" />
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
         <option name="package" value="com.android.providers.media.tests" />
-        <option name="runner" value="android.support.test.runner.AndroidJUnitRunner" />
+        <option name="runner" value="androidx.test.runner.AndroidJUnitRunner" />
         <option name="hidden-api-checks" value="false"/>
     </test>
 </configuration>