Use node prefix for build-in modules (#3340)

It is basically a cosmetic thing, but has the following advantages:

1. Consistency with the official node documentation. The prefix is used
there.
2. It is easier to recognize the build-in modules.

tests/electron/env_spec.js

@@ -1,4 +1,4 @@
-const events = require("events");
+const events = require("node:events");
 const helpers = require("./helpers/global-setup");
 
 describe("Electron app environment", () => {