Add .cjs and .mjs files support to test runner

Created by: ai

Node.js added new .cjs and .mjs file extensions for dual ESM/CJS packages.

This PR adds .cjs and .mjs files from node_modules support to test runner.

Context

I have popular dual CJS/ESM package.

  "type": "module",
  "main": "index.cjs",
  "module": "index.js",
  "browser": {
    "./index.js": "./index.browser.js"
  },
  "exports": {
    ".": {
      "require": "./index.cjs",
      "import": "./index.js",
      "browser": "./index.browser.js"
    },

Everythings works in Create React App npm start:

import { nanoid } from 'nanoid'

But Jest can’t load my library during npm test:

TypeError: (0 , _nanoid.nanoid) is not a function

Here is issue in my repo: https://github.com/ai/nanoid/issues/205

The Way to Reproduce the Problem

1. Create an empty CRA project
2. npm i nanoid
3. Create test:

   import * as nanoid from 'nanoid'
   console.log(nanoid)

Right now output will be:

{ default: 'index.cjs' }

With this pull request the result will be correct:

{ nanoid: [Function nanoid], urlAlphabet: …, customAlphabet: …, customRandom: … }