SDK / exoplayer

Following test cases are added:
1. Mux H264 video
2. Mux H265 video
3. Mux HDR video

Each test case performs following actions:
1. Extract track and samples from input Mp4 using MediaExtractor.
2. Feed those samples into Mp4 muxer.
3. Use extractor to extract the samples from muxed file and create dump file.

PiperOrigin-RevId: 512589069