test: fix test-cluster-net-listen-relative-path.js to run in /

test-cluster-net-listen-relative-path fails if run from the root
directory on POSIX because the socket filename isn't quite long enough.
Increase it by 2 so that the path length always exceeds 100 characters.

PR-URL: #34820
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ricky Zhou <0x19951125@gmail.com>

test/parallel/test-cluster-net-listen-relative-path.js

@@ -17,7 +17,7 @@ const tmpdir = require('../common/tmpdir');
 
 // Choose a socket name such that the absolute path would exceed 100 bytes.
 const socketDir = './unix-socket-dir';
-const socketName = 'A'.repeat(100 - socketDir.length - 1);
+const socketName = 'A'.repeat(101 - socketDir.length);
 
 // Make sure we're not in a weird environment.
 assert.ok(path.resolve(socketDir, socketName).length > 100,