video-split: speed-up test

src/call.cpp

src/call.h

src/conference.cpp

src/conference.h

src/manager.cpp

src/manager.h

src/media/video/sinkclient.cpp

src/media/video/sinkclient.h

src/media/video/video_receive_thread.cpp

src/sip/sipcall.cpp

src/sip/sipcall.h

test/unitTest/call/conference.cpp