isomp4: atomsrecovery: handle common and large atom headers
isomp4: atomsrecovery: handle common and large atom headers

Do not assume all files are large files. Check and use the short or
extended atom size field only if needed.

https://bugzilla.gnome.org/show_bug.cgi?id=784258

GStreamer/gst-plugins-good,GrokImageCompression/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,GrokImageCompression/gst-plugins-good,StreamUtils/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,StreamUtils/gst-plugins-good,GStreamer/gst-plugins-good,GStreamer/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good,StreamUtils/gst-plugins-good,GrokImageCompression/gst-plugins-good