Add a unit test covering av_stereo3d_alloc, av_stereo3d_alloc_size,
av_stereo3d_create_side_data, av_stereo3d_type_name,
av_stereo3d_from_name, av_stereo3d_view_name,
av_stereo3d_view_from_name, and av_stereo3d_primary_eye_name.
The from_name calls are driven by a static name table so each
string appears exactly once. Round-trip inverse checks verify
that type_name/from_name and view_name/view_from_name are
consistent with each other.
Coverage for libavutil/stereo3d.c: 0.00% -> 100.00%
Signed-off-by: marcos ashton <marcosashiglesias@gmail.com>