process: simplify check in previousValueIsValid()

This commit replaces a call to Number.isFinite() with a
cheaper typeof check. The subsequent range checks ensure that
the checked value is finite.

PR-URL: nodejs#24836
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/internal/process/per_thread.js

@@ -85,7 +85,7 @@ function setupCpuUsage(_cpuUsage) {
   // Ensure that a previously passed in value is valid. Currently, the native
   // implementation always returns numbers <= Number.MAX_SAFE_INTEGER.
   function previousValueIsValid(num) {
-    return Number.isFinite(num) &&
+    return typeof num === 'number' &&
         num <= Number.MAX_SAFE_INTEGER &&
         num >= 0;
   }