Investigate flaky parallel/test-fs-readdir-stack-overflow

[Trott]

• Version: 11.0.0-pre (master)
• Platform: pi3-docker
• Subsystem: test fs

https://ci.nodejs.org/job/node-test-binary-arm/3201/RUN_SUBSET=2,label=pi3-docker/console

00:22:20 not ok 304 parallel/test-fs-readdir-stack-overflow
00:22:20   ---
00:22:20   duration_ms: 240.132
00:22:20   severity: fail
00:22:20   exitcode: -15
00:22:20   stack: |-
00:22:20     timeout

[Trott]

Seems like this test is long-running on pi3-docker when it's successful (more than 30 seconds) which suggests that it might be something we want to move to sequential or maybe skip on machines that don't have a certain threshold of resources or something else?

[kibertoad]

@Trott Are you sure this is not a regression? Knex.js tests started timing out on fs.readdir invokation on 10.10.0, while 10.9.0 works fine.

Update: my apologies, seems to be an issue with mock-fs not being compatible with new Node and not in Node.js per se.