[C++] Convert `SingularOrList` to `is_in` when possible

[westonpace]

Describe the enhancement requested

Currently, when we encounter SingularOrList from Substrait, we convert it into an or list. In other words, expr1 || expr2 || expr3 || expr4. However, when all of the expressions are of the form field == literal (where field is the same) then we can replace it with is_in(field, [literal1, literal2, ..., literalN]).

This is arguably a little bit on the "planner/optimizer" slippery slope but it's a simple enough optimization and we already have an is_in function so I think it's a reasonable one to apply.

Component(s)

C++