SDK / exoplayer

We have our snazzy new file-based extractor tests now,
and the other ones have historically proven way more
hassle than they're worth (e.g. I spent a good few hours
once just trying to work out how to fix the Mp4 extractor
test, having established it was the test and not the
code that was broken!).

I think some more can go from the ogg package, but leaving
in place for now because it's a bit less clear what to
get rid of.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=125330072