Change Request: Replace `npm-run-all2` with a native script to reduce the dependency footprint

### Which packages would you like to change?

- [x] `espree`
- [ ] `eslint-scope`
- [ ] `eslint-visitor-keys`

### What problem do you want to solve?

In this issue, I would like to suggest replacing the `npm-run-all2` package with a native script to reduce the dependency footprint.

Currently, the `npm-run-all2` package is only used in the `espree` package as a devDependency, and it is only used when running the test scripts `test:cjs` and `test:esm`.


### What do you think is the correct solution?

The `npm-run-all` script can be simply replaced with a native script:

```diff
- "npm-run-all -s test:*"
+ "npm run test:cjs && npm run test:esm"
```

Also, `eslint-visitor-keys` follows this strategy:
https://github.com/eslint/js/blob/main/packages/eslint-visitor-keys/package.json#L51

### Participation

- [x] I am willing to submit a pull request for this change.

### Additional comments

_No response_

[]