Implement support for Swift frozen structs in Mono runtime

[kotlarmilos]

Description

This issue tracks the implementation of the Swift frozen struct lowering in Mono runtime. The Swift runtime enregisters frozen structs as a set of primitives if the sequence <= 4 machine words. The Mono runtime should utilize the lowering API and implements the same behavior as the Swift runtime when interoperating with Swift in JIT/AOT and interpreter configurations.

The lowering algorithm is implemented in . The Mono runtime should utilize the lowering API and have the same behavior as Swift runtime when interop with Swift in JIT/AOT and interpreter configurations.

The existing runtime tests should be used for validation.

Tasks

• [mono][swift-interop] Support for Swift frozen struct lowering in mini-JIT/AOT/interpreter #102143
• Support Swift frozen struct returns for pinvokes in JIT/AOT and interpreter configurations
• Support Swift frozen struct for callbacks in JIT/AOT and interpreter configurations
• (optional) Add cache that maps structs to computed lowering (SwiftPhysicalLowering). The goal is to eliminate repeated runs of lowering algorithm for "known" structs.