Fix passing IStringable array by ref scenarios

[manodasanW]

• MarshalInterface was missing CopyAbiArray causing for scenarios where an array of interfaces such as IStringable is passed by ref to not compile. This PR adds that function.
• Added the test cases from the testwinrt repo that validates these scenarios
• One of the test cases ended up discovering another issue where the FromAbi API can be called with a ThisPtr which isn't for the default interface and end up calling the wrong API. Handled this by doing a QueryInterface via As to make the test pass, but I believe this is a generic problem that can affect any class and needs a generic fix.

Fixes #352