investigate failing test-fs-readdir-ucs2 on Raspberry Pi

[Trott]

• Version: master
• Platform: Raspberry PI
• Subsystem: test

From nodejs/build#774:

parallel/test-fs-readdir-ucs2 is failing on all of the Pi's: Error: EINVAL: invalid argument, open '/home/iojs/build/workspace/node-test-binary-arm/test/tmp.0/=���', this is likely to be to do with it being on an NFS share exported from a ZFS volume. I'm going to have to defer to @nodejs/testing to figure out how to handle that special case. Let me know if there's something I should be doing for that mount to enable UCS2 (no promises that it's achievable on my end tho).

[Trott]

Fix in #14029

[refack]

Two follow up issues:

1. the UCS2 string break TAP parsing https://ci.nodejs.org/job/node-test-binary-arm/9039/RUN_SUBSET=6,label=pi1-raspbian-wheezy/tapResults/
2. test throws ENOENT in WSL (when using shared NTFS mounts):

$ NVM_NODEJS_ORG_MIRROR=https://nodejs.org/download/nightly Now using node v9.0.0-nightly20170703fe730d34ce (npm v5.0.3)

$ node test/parallel/test-fs-readdir-ucs2.js
/mnt/d/code/node-cur/test/parallel/test-fs-readdir-ucs2.js:22
  throw e;
  ^

Error: ENOENT: no such file or directory, open '/mnt/d/code/node-cur/test/tmp/=�♦�'
    at Object.fs.openSync (fs.js:651:18)
    at Object.<anonymous> (/mnt/d/code/node-cur/test/parallel/test-fs-readdir-ucs2.js:18:19)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Function.Module.runMain (module.js:605:10)
    at startup (bootstrap_node.js:158:16)
    at bootstrap_node.js:575:3

and assertion fails on native WSL volume:

refael@refaelux:~/node$ node test/parallel/test-fs-readdir-ucs2.js
assert.js:55
  throw new errors.AssertionError({
  ^

AssertionError [ERR_ASSERTION]: <Buffer 3d d8 04 dc> deepStrictEqual <Buffer 3d ef bf bd 04 ef bf bd>
    at fs.readdir.common.mustCall (/home/refael/node/test/parallel/test-fs-readdir-ucs2.js:29:10)
    at /home/refael/node/test/common/index.js:518:15
    at FSReqWrap.oncomplete (fs.js:135:15)