perf_hooks: reducing overhead of performance observer entry list

[H4ad]

Continuing the work started on nodejs/performance#109.

 confidence improvement accuracy (*) (**) (***) perf_hooks/performance-observer.js pending=1 n=100000 *** 147.63 % ±3.89% ±5.23% ±6.89% perf_hooks/performance-observer.js pending=10 n=100000 *** 104.54 % ±5.69% ±7.60% ±9.92% Be aware that when doing many comparisons the risk of a false-positive result increases. In this case, there are 2 comparisons, you can thus expect the following amount of false-positive results: 0.10 false positives, when considering a 5% risk acceptance (*, **, ***), 0.02 false positives, when considering a 1% risk acceptance (**, ***), 0.00 false positives, when considering a 0.1% risk acceptance (***) 

cc @nodejs/performance

[mscdex]

I don't know if it's a common case or not, but it may/may not be worth guarding the sort with a conditional that checks if entries.length > 1 before sorting.

[H4ad]

I added, I got 8% faster for 1 item but degraded the else path by ~8%, so I didn't think that was worth it since probably this queue will be called with more items than 1.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/54464/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/54514/

[nodejs-github-bot]

Landed in 328bdac