Prevent panic when slicing end is higher than nodes array size

[asettouf]

Hi,

first time contributing on this project (which I find lovely), so let me know if there is anything I can make to improve this PR.

Solves #1487

[codecov-io]

Codecov Report

Merging #1756 (88dcffc) into master (cfedc92) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1756      +/-   ##
==========================================
- Coverage   71.51%   71.44%   -0.08%     
==========================================
  Files         178      178              
  Lines       13775    13775              
==========================================
- Hits         9851     9841      -10     
- Misses       3312     3322      +10     
  Partials      612      612              

Flag	Coverage Δ
ubuntu	71.40% <100.00%> (-0.06%)	⬇️
windows	70.01% <100.00%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
js/modules/k6/html/html.go	81.95% <100.00%> (ø)
core/engine.go	90.95% <0.00%> (-2.02%)	⬇️
lib/executor/vu_handle.go	93.33% <0.00%> (-1.91%)	⬇️
js/runner.go	80.45% <0.00%> (-0.66%)	⬇️
stats/cloud/collector.go	79.81% <0.00%> (-0.64%)	⬇️

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[na--]

Thanks!

[asettouf]

@na-- I'm just a bit surprised I'm decreasing the coverage. Should I add more tests for html.go, on the Slice function?

[imiric]

LGTM, thanks for the fix!

I would've preferred a more unit-focused test to avoid testing the js.Runner for this, but it's not a big deal.

As for the Codecov report, don't worry about it. It's frequently wrong and we want to replace it with something better, but haven't gotten around to it. 😞