fix(core): fix worker threads in Node >=11.10.0

[ehmicky]

Fixes #130.

Follow up on #127.

In worker threads, process.chdir used to be undefined. However since Node 11.10.0 it is now a noop function with a disabled: true property.

[codecov]

Codecov Report

Merging #132 into master will not change coverage by %.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #132   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            7         7           
  Lines          162       162           
  Branches        34        34           
=========================================
  Hits           162       162           

Impacted Files	Coverage Δ
lib/util/resolveCommand.js	100.00% <100.00%> (ø)

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