SDK / exoplayer

This CL removes the prefixes to the tests added after https://github.com/google/ExoPlayer/commit/a6d0caaa3c95746beb4e82c1005c06cbb14b6f6c.

This CL is generated by following command
$ find -name '*Test.java' | xargs -I{} sed -i 's/^\ \ public\ void\ test\([A-Z]\)\(.*\)$/  public void \L\1\E\2/' {}

PiperOrigin-RevId: 300547504