Type mismatches when using Interfaces with _NoncopyableType decoration about slang

[csyonghe]

The issue here is calling for some language design around non copyable types.

Copyability is currently not a concept modeled in the type system, and we generally assume all types are copyable.
When a builtin type is decorated as [NonCopyableType], we enable some special IR gen rules to avoid generating copies, but this is completely transparent to the type system, and therefore leading to issues such as when specializing a generic function with non copyable type.

WIthout extending the type system to reason about copyability, our best solution here is to disallow non copyable type to implement any interface.

[swoods-nv]

Leaving this as backlog for now, because this is an internal compiler interface, but should get cleaned up once we're on to tail end test perfection.

[swoods-nv]

Compiler internals only, no plan to address, so closing as not planned.