[APM-CI][Node.js] Add random delays to some requests to simulate abnormalities

[watson]

[beniwohli]

I'd try to do introduce non-random abnormalities. There's not really much of a story to tell when you simply have a sleep(randint) somewhere.

I don't really have a great suggestion yet how to introduce semi-realistic delays that would serve as a nice demo for how to debug a performance issue, though :(

[kuisathaverat]

toxiproxy is a good tool to stimulate this kind of network anomalies.