Migrate away from deprecated test classes

There are some unnecessary imports, test dependencies, and explicit casts
now, but we don't have reasonable tooling to clean those up automatically
across the entire codebase. Also, some imports may be out of order.

Fixes: 119834874
Test: ./gradlew buildOnServer
Change-Id: Ic48c88f4f03f890651fc9cdabdefdc82774dcdf5
diff --git a/paging/rxjava2/build.gradle b/paging/rxjava2/build.gradle
index 413c410..ac29079 100644
--- a/paging/rxjava2/build.gradle
+++ b/paging/rxjava2/build.gradle
@@ -39,6 +39,8 @@
     androidTestImplementation(JUNIT)
     androidTestImplementation(MOCKITO_CORE, libs.exclude_bytebuddy) // DexMaker has it"s own MockMaker
     androidTestImplementation(DEXMAKER_MOCKITO, libs.exclude_bytebuddy) // DexMaker has it"s own MockMaker
+    androidTestImplementation(TEST_EXT_JUNIT)
+    androidTestImplementation(TEST_CORE)
     androidTestImplementation(TEST_RUNNER)
     androidTestImplementation(ESPRESSO_CORE)
     androidTestImplementation(KOTLIN_STDLIB)