Fix MATLAB in-out parameter semantics when input and output share a name

[bardo84]

Category

Common script semantics and runtime correctness

Problem

Function signatures where an input and an output share the same name do not currently behave correctly.

Intent

This is part of MATLAB function semantics and affects normal script/function authoring patterns.

Done When

• in-out parameter cases with shared names behave correctly for supported MATLAB-compatible forms
• representative regression coverage exists for the failing pattern