Simplify CPU count detection

Use Math.max(1, os.cpus()?.length || 1) to replace
try/catch + manual guards while keeping behavior equivalent
on Node 20 environments.

Author: PeterDaveHello

build.mjs

@@ -32,14 +32,7 @@ if (cacheCompressionEnv != null) {
     cacheCompressionOption = false
   }
 }
-let cpuCount = 1
-try {
-  const cpuInfo = os.cpus && os.cpus()
-  const len = Array.isArray(cpuInfo) ? cpuInfo.length : 0
-  cpuCount = Number.isInteger(len) && len > 0 ? len : 1
-} catch {
-  cpuCount = 1
-}
+const cpuCount = Math.max(1, os.cpus()?.length || 1)
 const rawWorkers = process.env.BUILD_THREAD_WORKERS
   ? parseInt(process.env.BUILD_THREAD_WORKERS, 10)
   : undefined