path: inline conditions

This condition can be inlined in the first `if` statement since
if the `path`'s length is 0, it'll be a empty string so we can
return that as there's no need for an extra `if` statement.

PR-URL: https://github.com/nodejs/node/pull/38613


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>