test(system): add valid 0 for cron

[Shinigami92]

While working on

• test: run tests shuffled #1645

it reports an failure for https://github.com/faker-js/faker/actions/runs/4025222101/jobs/6918173202#step:7:302

but 0 is a valid digit for cron

[codecov]

Codecov Report

Merging #1787 (9e2a514) into next (7bc4a09) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             next    #1787   +/-   ##
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  Coverage   99.65%   99.65%           
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  Files        2340     2340           
  Lines      242622   242622           
  Branches     1113     1113           
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  Hits       241786   241786           
  Misses        815      815           
  Partials       21       21           

[Shinigami92]

This PR targeted the wrong goal and was meant to fix the shuffled tests
Now we want to change the whole implementation of the test itself
Therefore it's up to be grepped by someone who wants to fix it

[xDivisionByZerox]

I'll provide a follow up PR which addresses this test reimplementation.

[xDivisionByZerox]

After checking the source I noticed that the fix for the test was totally valid.
includeNonStandard is misleading in that way that it doesn't guarantee that a non standard expression is returned. Thats why we simply have to check whether a number/astrics (standard) or an @ (non standard) is returned.

The title should probably simply be adjusted to state 'should be able to return non-standard cron expressions'.

please provide a new review