Is your feature request related to a problem or challenge? Please describe what you are trying to do.
In #3252 we added support for SQL IS [NOT] TRUE/FALSE by mapping to the existing logical binary operator Is[Not]DistinctFrom. This resulted in a small PR compared to introducing new Expr variants such as IsNotTrue, but the downside is that we are now unable to implement type validation/coercion to ensure that the left expression is a boolean value.

Describe the solution you'd like
Introduce new Expr variants but still map to the physical plan for IsDistinctFrom.

Describe alternatives you've considered
None

Additional context
None