ramp-resources: timeout of test "HTTP proxy responses responds with 503 when backend is down"

Since 0.5.0 and probably before; mostly on Windows but principally any platform

Reproduce:

get a maximally slow machine, preferrably Windows XP, and load it heavily. E.g. virus scan + DVD burn + recording from TV card
in ramp-resources/ run node test/http-proxy-test.js

Note: poor Windows ppl might have a hard time getting a setup. They may find helpful this post / this script.

Yields:

Timeout: HTTP proxy responses responds with 503 when backend is down
    -> test function
    TimeoutError: Timed out after 250ms

Note: This originally popped up in ramp-resources/pr#2, about here. The things extracted from there are this issue and #336.

busterjs / buster