[DAG] visitFREEZE - generalize freeze(op()) -> op(freeze()) to any number of operands

[DAG] visitFREEZE - generalize freeze(op()) -> op(freeze()) to any number of operands

canCreateUndefOrPoison currently only handles unary ops, but we intend to change that soon - this more closely matches the pushFreezeToPreventPoisonFromPropagating behaviour where the freeze is pushed up to a single operand value, as long as all others are guaranteed not to be poison/undef.

However, pushFreezeToPreventPoisonFromPropagating would freeze all uses of the value - whilst this variant requires the frozen value to be only used in the op - we can look at generalize multiple uses later if the need arises.