ci: run windows tests and also run them concurrently (#7758)

test/js/node/buffer.test.js

@@ -1,3 +1,4 @@
+// @known-failing-on-windows: 1 failing
 import { Buffer, SlowBuffer, isAscii, isUtf8 } from "buffer";
 import { describe, it, expect, beforeEach, afterEach } from "bun:test";
 import { gc } from "harness";