refactor: remove unused timeout parameter in portIsFree

[copperwall]

timeout is specified as an optional parameter with a default value of
9999. portIsFree doesn't have any callsites that use this optional
parameter, so this removes the parameter and leaves the timeout value as
a local variable in the function. portIsFree isn't exported outside of
_inspect.js, so this doesn't change any public function interfaces.

[Trott]

Hi, there! node-inspect is now part of Node.js core. If you want to open a PR for this in the main repository, I'd be supportive of the change. The relevant file is in lib/internal/inspector/_inspect.js although there is a PR open to move it to lib/internal/debugger/_inspect.js so if that previous file is missing, look for that latter file.

In the meantime, this repository is being tidied up in preparation for archiving, so I'm going to close this PR. Sorry it didn't land back when you opened it!