fix: cpus().length is broken under docker. (#100)

cgroups don't mask off unavailable CPUs and this is considered a
feature not a bug, and so Node got os.availableParallelism() to
attempt to fix this.

This version still has issues (nodejs/node#59200)
but at least it's more likely to be correct.

Author: jdmarshall

lib/reporter/chart.js

@@ -1,4 +1,4 @@
-const { platform, arch, cpus, totalmem } = require("node:os");
+const { platform, arch, availableParallelism, totalmem } = require("node:os");
 const { styleText } = require("../utils/styleText");
 const { analyze } = require("../utils/baseline.js");
 
@@ -85,7 +85,7 @@ const timer = Intl.NumberFormat(undefined, {
 const environment = {
 	nodeVersion: `Node.js version: ${process.version}`,
 	platform: `${platform()} ${arch()}`,
-	hardware: `${cpus().length} vCPUs | ${(totalmem() / 1024 ** 3).toFixed(1)}GB Mem`,
+	hardware: `${availableParallelism()} vCPUs | ${(totalmem() / 1024 ** 3).toFixed(1)}GB Mem`,
 };
 
 /**

lib/reporter/html.js

@@ -1,4 +1,4 @@
-const { platform, arch, cpus, totalmem } = require("node:os");
+const { platform, arch, availableParallelism, totalmem } = require("node:os");
 const fs = require("node:fs");
 const path = require("node:path");
 
@@ -77,7 +77,7 @@ const generateHTML = (template, durations) => {
 
 	const environmentDiv = `<p>Node.js version: <span class="number">${process.version}</span></p>
 	<p>Platform: <span class="number">${platform()} ${arch()}</span></p>
-	<p>CPU Cores: <span class="number">${cpus().length}</span> vCPUs | <span class="number">${(totalmem() / 1024 ** 3).toFixed(1)}GB Mem</span></p>`;
+	<p>CPU Cores: <span class="number">${availableParallelism()}</span> vCPUs | <span class="number">${(totalmem() / 1024 ** 3).toFixed(1)}GB Mem</span></p>`;
 
 	return template
 		.replaceAll("{{CONTAINER_HEIGHT}}", `${durations.length * 100}px;`)