benchmark: capsnego: use GOptionContext for option parsing
benchmark: capsnego: use GOptionContext for option parsing

Lachann/gstreamer,jpakkane/gstreamer,mparis/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,centricular/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,krichter722/gstreamer,centricular/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,Lachann/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer,surround-io/gstreamer,mparis/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,surround-io/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,mparis/gstreamer,surround-io/gstreamer,Lachann/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,jpakkane/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,jpakkane/gstreamer,surround-io/gstreamer,centricular/gstreamer,surround-io/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,krichter722/gstreamer