test: deflake test-loaders-workers-spawned

PR-URL: #50251
Backport-PR-URL: #50669
Fixes: #50247
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Vinícius Lourenço Claro Cardoso <contact@viniciusl.com.br>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/es-module/test-loaders-workers-spawned.mjs

@@ -48,8 +48,14 @@ describe('Worker threads do not spawn infinitely', { concurrency: true }, () =>
     ]);
 
     assert.strictEqual(stderr, '');
+    // We are validating that:
+    // 1. the `--require` flag is run first from the main thread (and A is printed).
+    // 2. the `--require` flag is then run on the loader thread (and A is printed).
+    // 3. the `--loader` module is executed (and B is printed).
+    // 4. the `--import` module is evaluated once, on the main thread (and C is printed).
+    // 5. the user code is finally executed (and D is printed).
     // The worker code should always run before the --import, but the console.log might arrive late.
-    assert.match(stdout, /^A\r?\nA\r?\n(B\r?\nC|C\r?\nB)\r?\nD\r?\n$/);
+    assert.match(stdout, /^A\r?\n(A\r?\nB\r?\nC|A\r?\nC\r?\nB|C\r?\nA\r?\nB)\r?\nD\r?\n$/);
     assert.strictEqual(code, 0);
     assert.strictEqual(signal, null);
   });