Currently only the calling convention is passed on from the prototype to the built call instruction. This patch also copies the parameter attributes.
This seems to be needed after D101806, which changed the instruction selector to only look at the call instruction parameter attributes, whereas before it also looked at the called function.
There are probably more places that needs a similar fix, like builtins..?
This makes the "verifier extension" (D103412) pass on SPEC17/SystemZ. Not sure if the returned value is checked by that patch or if they need a similar handling like the parameters?