test: verify inspector help url works

This commit adds basic functionality testing of the
help URL printed when the inspector starts.

PR-URL: https://github.com/nodejs/node/pull/19887
Refs: https://github.com/nodejs/node/pull/19871


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>