Join - warn if predicate doesn't use both LeftRecord and RightRecord

[MikeStall]

Join() should warn if predicate doesn't use both LeftRecord and RightRecord.

This would flag cases like this, which could produce surprising results:
Join(Sequence(3), Sequence(3), LeftRecord.Value in [1,2], JoinType.Left, RightRecord.Value As R2)

Filter() has same issue

We have a basic warning for literals:
Filter([10,20,30], true)

But no warning for:
Filter([10,20,30], true && true)