Test Linq.Expression interpreted mode in CI

We had some recent test changes that would not be runnable under AOT for sure and nothing was broken. That proves that we do not run Linq.Expressions with AOT.

Also, attempts to run tests with AOT wee not very successful.

We need to make sure the tests are runnable with AOT.

That includes figuring out how to exclude scenarios that are known not AOT compatible - like usage of Reflection.Emit in tests. Most likely introduce some #if in the code and, parameterise the csproj file to not take dependencies on stuff like Ref.Emit when targeting AOT.