Add crypto.randomBytes

[bookmoons]

Adds method randomBytes to k6/crypto. The method takes a single parameter size specifying byte count and returns an array of random bytes. Bytes are represented as number literals.

Toward #900.

[codecov-io]

Codecov Report

Merging #922 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #922      +/-   ##
==========================================
+ Coverage   69.77%   69.82%   +0.05%     
==========================================
  Files         112      112              
  Lines        8815     8823       +8     
==========================================
+ Hits         6151     6161      +10     
+ Misses       2262     2261       -1     
+ Partials      402      401       -1

Impacted Files	Coverage Δ
js/modules/k6/crypto/crypto.go	97.47% <100%> (+0.18%)	⬆️
core/engine.go	93.92% <0%> (+0.93%)	⬆️

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[bookmoons]

AppVeyor failed on this, but it seems to be from a different part of the code. I don't think it's from the changes:

--- FAIL: TestRealTimeAndSetupTeardownMetrics (5.97s)

[bookmoons]

Codecov is showing 95.72%, but running locally I get 96.1%. Is it possible it doesn't rerun if the CI builds fail?

[mstoykov]

LGTM!
That test is known to be problematic #919 and I am thinking of disabiling it for now on appveyor as it mostly fails for no reason. On the point of coverage - I think codecov doesn't update when only files it doesn't track are changed and in this case only test are changed ... which is also not ideal :(

[bookmoons]

Should I be updating the copyright date on files I modify? It's a couple years old now.

[mstoykov]

I am pretty sure we should make some script or use some tool to update this automatically ...

[na--]

LGTM

[bookmoons]

Thanks for merging guys.