dynamic: vmray: add support for function return parameters

[mike-hunhoff]

See #2208 (comment)

We must first determine if capa can emit features from arrays without polluting the matches.

[mike-hunhoff]

Emitting these features will pollute the feature set that capa must process, specifically, for cases when a sample is resolving information in the sandbox environment where the return value(s) are not relevant and may cause FPs.