Convert core/tests/BroadcastRadioTests/Android.mk file to Android.bp

Cherrypick of https://googleplex-android-review.git.corp.google.com/c/platform/frameworks/base/+/6924098
See build/soong/README.md for more information.

Bug: 122332340
Test: treehugger
Change-Id: I8d270949cb2dd4391ceeaf57ea8557be849c9ed8
Merged-In: I8d270949cb2dd4391ceeaf57ea8557be849c9ed8