test: fix flaky test-worker-prof

Fixes: nodejs#26401

Author: Trott

test/sequential/test-worker-prof.js

@@ -49,9 +49,10 @@ if (process.argv[2] === 'child') {
   w.postMessage(process.execPath);
 } else {
   tmpdir.refresh();
+  const timeout = common.platformTimeout(30_000);
   const spawnResult = spawnSync(
     process.execPath, ['--prof', __filename, 'child'],
-    { cwd: tmpdir.path, encoding: 'utf8', timeout: 30_000 });
+    { cwd: tmpdir.path, encoding: 'utf8', timeout });
   assert.strictEqual(spawnResult.stderr.toString(), '',
                      `child exited with an error: \
                      ${util.inspect(spawnResult)}`);