Add testutils as test dep of library-core module
Add testutils as test dep of library-core module

The current workaround seems to cause compilation errors inside the
testutils module in Android Studio. This seems to fix them.

This doesn't introduce a circular dependency because it's only
the tests in library-core depending on testutils.

PiperOrigin-RevId: 281318192

androidx/media,androidx/media,google/ExoPlayer,amzn/exoplayer-amazon-port,ened/ExoPlayer,ened/ExoPlayer,stari4ek/ExoPlayer,google/ExoPlayer,google/ExoPlayer,androidx/media,stari4ek/ExoPlayer,stari4ek/ExoPlayer,amzn/exoplayer-amazon-port,amzn/exoplayer-amazon-port,ened/ExoPlayer