rsbench: also show %U time (total time of all threads)
rsbench: also show %U time (total time of all threads)

TIME(1):
U      Total number of CPU-seconds that the process
       used directly (in user mode), in seconds.

LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed