Stats printing: also print aggregated times.
Stats printing: also print aggregated times.

In addition to the hierarchical profile report, also print aggregate times
for all of the active leaf profile phases. This makes it easier to quickly
see the total time spent on ray intersections, for example.

nispaur/pbrt-v3,shihchinw/pbrt-v3,nyue/pbrt-v3,mmp/pbrt-v3,mmp/pbrt-v3,nyue/pbrt-v3,nispaur/pbrt-v3,ambakshi/pbrt-v3,nyue/pbrt-v3,ambakshi/pbrt-v3,mmp/pbrt-v3,ambakshi/pbrt-v3,nispaur/pbrt-v3,nispaur/pbrt-v3,shihchinw/pbrt-v3,shihchinw/pbrt-v3,nyue/pbrt-v3,mmp/pbrt-v3,shihchinw/pbrt-v3