Allow argument and result names replacement in predicates.

Allow argument and result names replacement in predicates.

    This allow specifying $x to refer to an operand's named argument (operand or attribute) or result. Skip variadic operands/results for now pending autogenerated discussion of their accessors.

    This adds a new predicate, following feedback on the naming but does not remove the old one. Post feedback I'll do that, potentially in follow up.

--

PiperOrigin-RevId: 250720003