test: do not use common.isMainThread

`common.isMainThread` was removed in
8caa1dcee63b2c6fd7a9, use the
`isMainThread` export of the `worker_threads` module instead.

PR-URL: #56768
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

test/parallel/test-require-resolve-opts-paths-relative.js

@@ -3,8 +3,9 @@
 const common = require('../common');
 const assert = require('assert');
 const fixtures = require('../common/fixtures');
+const { isMainThread } = require('worker_threads');
 
-if (!common.isMainThread)
+if (!isMainThread)
   common.skip('process.chdir is not available in Workers');
 
 const subdir = fixtures.path('module-require', 'relative', 'subdir');