Add Promise-based versions for some functions in child_process

What is the problem this feature will solve?

It would be nice if child_process functionality, such as exec and execFile, had Promised based versions by default. Currently it does not, see https://nodejs.org/api/child_process.html

Note that only child_process functions that can be async/await should be considered. This does not include things such as fork or spawn.

What is the feature you are proposing to solve the problem?

A new child_process/promises import path that can be used similar to how fs promises are used:

// Using ESM Module syntax:
import { exec } from 'child_process/promises';

try {
  const { stdout } = await exec(
    'sysctl -n net.ipv4.ip_local_port_range'
  );
  console.log('successfully executed the child process command');
} catch (error) {
  console.error('there was an error:', error.message);
}

The ask is basically that child_process/promises could just return a variant such as const exec = util.promisify(process.exec); as a convenience.

What alternatives have you considered?

I am already using const exec = util.promisify(process.exec); but that is not as nice. And this new proposal follows along what is happening in other Node.js APIs.

(The original ask in https://github.com/nodejs/node/issues/38823 was perceived as asking for the entire module and all APIs to be async/await. This issue here narrows it down to only focus on the functions that can be.)

首先，将提议的 child_process/promises 入口点与现有的 fs promises API 以及 issue #38823 中讨论的范围进行比较。确定应公开哪些支持 async 的 child_process 函数，然后验证 API 形态、文档和测试是否覆盖这些函数，但不包括 fork 或 spawn。