Allow Access types to be closely related

Capability/request summary

Currently, only the following types are deemed closely related (from 9.3.6):

— Abstract numeric types—Any abstract numeric type is closely related to any other abstract numeric type.

— Array types—Two array types are closely related if and only if the types have the same dimensionality and the element types are closely related

— Record types—Two record types are closely related if and only if each element has a matching element (see 9.2.3) in the other type and the corresponding types for matching elements are closely related.

No other types are closely related

Proposed changes

Allow access types to also be closely related if the 'DESIGNATED_SUBTYPEs are also closely related, similarly to how records types are deemed closely related.