TableGen: allow mixing attributes and operands in the Arguments DAG of Op definition

The existing implementation of the Op definition generator assumes and relies
on the fact that native Op Attributes appear after its value-based operands in
the Arguments list.  Furthermore, the same order is used in the generated
`build` function for the operation.  This is not desirable for some operations
with mandatory attributes that would want the attribute to appear upfront for
better consistency with their textual representation, for example `cmpi` would
prefer the `predicate` attribute to be foremost in the argument list.

Introduce support for using attributes and operands in the Arguments DAG in no
particular order.  This is achieved by maintaining a list of Arguments that
point to either the value or the attribute and are used to generate the `build`
method.

PiperOrigin-RevId: 237002921