cli: add --use-env-proxy

This does the same as NODE_USE_ENV_PROXY. When both are set,
like other options that can be configured from both sides,
the CLI flag takes precedence.

PR-URL: https://github.com/nodejs/node/pull/59151
Fixes: https://github.com/nodejs/node/issues/59100
Reviewed-By: Ilyas Shabi <ilyasshabi94@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/https.js

@@ -70,6 +70,7 @@ const { URL, urlToHttpOptions, isURL } = require('internal/url');
 const { validateObject } = require('internal/validators');
 const { isIP, isIPv6 } = require('internal/net');
 const assert = require('internal/assert');
+const { getOptionValue } = require('internal/options');
 
 function Server(opts, requestListener) {
   if (!(this instanceof Server)) return new Server(opts, requestListener);
@@ -599,7 +600,8 @@ Agent.prototype._evictSession = function _evictSession(key) {
 
 const globalAgent = new Agent({
   keepAlive: true, scheduling: 'lifo', timeout: 5000,
-  proxyEnv: process.env.NODE_USE_ENV_PROXY ? filterEnvForProxies(process.env) : undefined,
+  // This normalized from both --use-env-proxy and NODE_USE_ENV_PROXY settings.
+  proxyEnv: getOptionValue('--use-env-proxy') ? filterEnvForProxies(process.env) : undefined,
 });
 
 /**