In the past, this always measured the per-shader execution times of the
individual OSD parts, which was thrown off because the shader was reused
anyway. (And apparently recording the OSD shader execution times was
removed completely, probably because of them being so unrealiably
anyway)
Since ra_timer no longer has the restriction of not allowing timers to
run concurrently, we can just wrap the entire OSD block inside a single
osd_timer now, and record that. (Technically, this can still be off when
using --blend-subtitles=video/yes and showing a full-screen OSD at the
same time. Maybe this can be done better?)