Investigate flaky test-fs-readfile-tostring-fail

[Trott]

Example failure:

• ubuntu1404-32

[Trott]

Stress test: https://ci.nodejs.org/job/node-stress-single-test/92/nodes=ubuntu1404-32/

[Trott]

It looks like the issue is that the test can take 20 or 30 seconds on ubuntu1404-32 under ordinary conditions and so a hiccup of some kind can make it exceed the 60 second timeout implemented by the test runner.

[Trott]

Stress test came up clean (with the 20-30 second caveat mentioned above). This never came up as flaky before so I'm going to close it. It looks like maybe all that happened was the host was bogged down for some reason and tests that normally take a long time took a Very Long Time and timed out. If this comes up again, we can re-open this or open a new ticket and explore it some more.

[joaocgreis]

Happened again on a Raspberry: https://ci.nodejs.org/job/node-test-binary-arm/2650/RUN_SUBSET=6,label=pi2-raspbian-wheezy/console

Not reopening this issue since it failed by timeout and could be a hiccup, but reporting this just in case we see more of it soon and need to start investigating.