test: verify threadId in reports

PR-URL: #31556
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Richard Lau <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Chengzhong Wu <[email protected]>
Reviewed-By: Rich Trott <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>

test/report/test-report-worker.js

@@ -23,6 +23,7 @@ async function basic() {
   helper.validateContent(report);
   assert.strictEqual(report.workers.length, 1);
   helper.validateContent(report.workers[0]);
+  assert.strictEqual(report.workers[0].header.threadId, w.threadId);
 
   w.postMessage({});