FLAC: support files which has ID3v2 tag or Last-metadata-block flag is 1

Problem:
1. Some flac audios cannot be played because they have ID3v2 tag
2. flac audio which Last-metadata-block flag is 1 cannot be played
   by default

Solution:
1. Skip ID3v2 tag, and make these flac audios can be played
2. Last-metadata-block flag can be 1 according to flac spec.
   https://xiph.org/flac/format.html#metadata_block_streaminfo
   It is rational that flac files only have one metadata block
   (STREAMINFO) before audio frames.
   So, we should support files which Last-metadata-block is 1.

Bug: 122939727
Test: 1. manually play flac audio with ID3v2 tag
2. manually play flac audio which Last-metadata-block is 1

Change-Id: Id4928bc3a597176be63130bce9ba25df1978b51d