src,lib: optimize nodeTiming.uvMetricsInfo

[RafaelGSS]

$ node benchmark/compare.js --old ./node-without --new ./node-with --filter "nodetiming" perf_hooks > res.out && node-benchmark-compare res.out [00:00:43|% 100| 1/1 files | 60/60 runs | 3/3 configs]: Done confidence improvement accuracy (*) (**) (***) perf_hooks/nodetiming-uvmetricsinfo.js events=1 n=1000000 *** 467.03 % ±12.50% ±16.82% ±22.27% perf_hooks/nodetiming-uvmetricsinfo.js events=1000 n=1000000 *** 479.78 % ±11.29% ±15.17% ±20.04% perf_hooks/nodetiming-uvmetricsinfo.js events=10000 n=1000000 *** 486.76 % ±9.85% ±13.23% ±17.46% Be aware that when doing many comparisons the risk of a false-positive result increases. In this case, there are 3 comparisons, you can thus expect the following amount of false-positive results: 0.15 false positives, when considering a 5% risk acceptance (*, **, ***), 0.03 false positives, when considering a 1% risk acceptance (**, ***), 0.00 false positives, when considering a 0.1% risk acceptance (***)