Implement support for copy constructors when marshalling in IJW (dotnet/coreclr#22805)
Fixes dotnet/coreclr#22219.
I decided to try simplifying the code when bringing this feature over from .NET Framework. The .NETFX x86 implementation of this marshaler adds a lot of extra code-paths, and intercepts the calling stub to enable it to exactly replicate the behavior of what would be the native code by copy-constructing an object in-place where it goes on the stack for the native call.
Instead of adding all of that extra goo, I decided to keep the implementation much more similar to the non-x86 implementation from .NETFX. Instead of intercepting the call and adding bookkeeping helper stubs, the marshaler just copies to a local in the IL stub, just like non-x86. When calling the native function, it just loads the local onto the IL stack and calls the native function as a normal function. There is a difference there, but I cannot think of a way that the difference is observable to the user.
The non-x86 implementation is identical to the .NETFX implementation.
Commit migrated from https://github.com/dotnet/coreclr/commit/
4bca72836811aa1b82389c50dc4f2bcae222bdc0