Tests for "can selector become true by modifier" for simple $-operators
Fix wrong tests, separate "complex" tests to a separate scope.
Now Matcher.canBecomeTrueByModifier deals with simple $-operators with scalars:

- $gt, $gte, $lt, $lte
- $ne
- $nin, $in
More tests
Fix the way $in analysis worked
Catch if modifier surely modifies object when scalar expected
Update the comment in tests section
Fallback to "YES" in a case of noticeable floating point numbers underflow
Polish canBecomeTrueByModifier operators optimization

- Fix the pruning `expectedScalarIsObject`
- Limit $gt,$lt,... to numbers only (since there needs to be more logic to support dates and strings later)
- Add comments on dubious parts