src: simplify loop arithmetic in GetCPUInfo

[gireeshpunathil]

Cache the repeated operations and reuse; potentially generating
efficient code in some platforms, and improving readability.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[nodejs-github-bot]

@gireeshpunathil build started: https://ci.nodejs.org/blue/organizations/jenkins/node-test-pull-request-lite-pipeline/detail/node-test-pull-request-lite-pipeline/2656/pipeline

[gireeshpunathil]

CI: https://ci.nodejs.org/job/node-test-pull-request/20880/

[ZYSzys]

Since we are here, how about do the same thing on js land too for consistency ?

node/lib/os.js

Lines 88 to 106 in 8375c70

	function cpus() {
	// [] is a bugfix for a regression introduced in 51cea61
	const data = getCPUs() || [];
	const result = [];
	for (var i = 0; i < data.length; i += 7) {
	result.push({
	model: data[i],
	speed: data[i + 1],
	times: {
	user: data[i + 2],
	nice: data[i + 3],
	sys: data[i + 4],
	idle: data[i + 5],
	irq: data[i + 6]
	}
	});
	}
	return result;
	}

[gireeshpunathil]

@ZYSzys - done, thanks!

[danbev]

Landed in e51da1f.