Translate dom/media/gtest/mp4_demuxer/TestParser.cpp test cases to rust

[baumanj]

There are quite a few test cases in TestParser.cpp that depend on behavior in this repo which isn't covered by local tests. To provide earlier feedback and avoid failures like https://bugzilla.mozilla.org/show_bug.cgi?id=1681811#c3, it would be helpful to add tests based on these files to this repo