simplify nanobench --quiet / -q output

This tries to cut things down to the very minimum you might want to know:

$ out/Release/nanobench --match nytimes --config 8888 gpu -q
Timer overhead: 29.6ns
! -> high variance, ? -> moderate variance
    micros       bench
   2479.05 !    desk_nytimes.skp_1_mpd    8888
   1313.92      desk_nytimes.skp_1_mpd    gpu
   3617.65      desk_nytimes.skp_1    8888
   1158.34      desk_nytimes.skp_1    gpu
   1368.99 !    keymobi_nytimes_com_.skp_1_mpd    8888
    393.40      keymobi_nytimes_com_.skp_1_mpd    gpu
   1179.68 !    keymobi_nytimes_com_.skp_1    8888
    342.74      keymobi_nytimes_com_.skp_1    gpu

All times are printed in microseconds, and high variance runs are marked.

BUG=skia:

Review URL: https://codereview.chromium.org/1493313003
1 file changed