[LLVM 20] Update tests.

[hvdijk]

Overview

[LLVM 20] Update tests.

Reason for change

Describe how the current behaviour of the project is causing problems for you
or is otherwise unsatisfactory for your use case.

Description of change

loop_call_instantiation sees an extra flag added to icmp. Allow that.

struct_select hits a new optimization that happens because both structure elements are the same type. Use different types to get the same IR we got before.

Anything else we should know?

If there's any other relevant information we should know that may help us in
understanding and verifying your patch, please include it here.

Checklist

• Read and follow the project Code of Conduct.
• Make sure the project builds successfully with your changes.
• Run relevant testing locally to avoid regressions.
• Run clang-format-19 on all modified code.