feat(instrumenter): add expression mutator for Date (#4917)

[boretti]

It would be interesting to have mutation produced for operation on Date.

Expression like :

aDate.setDate(aDate.getDate()+1)

will produce interesting mutation based on the +1. It would also be interesting to have mutation changing the setDate or getDate operation (as updating month and not the day of month).

I propose to add the following mutation (to method-expression-mutator) :

• getDate to/from getMonth
• setDate to/from setMonth
• getHours to/from getMinutes
• setHours to/from setMinutes

See issue #4917

[boretti]

Update based on proposal in the issue.

[nicojs]

The code looks great, But I first want to resolve the discussion in #4917 before merging

[boretti]

Updated according exchange in the issue

[nicojs]

Thanks! ❤️