test: move tests with many workers to sequential

These tests spawn many workers, which may be CPU intensive causing
timeouts (see the referenced PR for more details). Let's move them
to sequential.

Refs: #44090
PR-URL: #44139
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

Author: kvakil

test/parallel/test-worker-fshandles-error-on-termination.js test/sequential/test-worker-fshandles-error-on-termination.js

@@ -5,7 +5,7 @@ if (!common.hasCrypto)
 const assert = require('assert');
 const http2 = require('http2');
 const makeDuplexPair = require('../common/duplexpair');
-const { Worker, parentPort } = require('worker_threads');
+const { parentPort, Worker } = require('worker_threads');
 
 // This test ensures that workers can be terminated without error while
 // stream activity is ongoing, in particular the C++ function