Add callvirt support for implicit interface method implementations

[puff]

Using callvirt on implicit implementations of interface methods throws a MissingMethodException.
Example:

var module = ModuleDefinition.FromModule(typeof(Usage).Module);
var method = module.GetAllTypes().FirstOrDefault(x => x.Name == "Usage")?.Methods.First(x => x.Name == "Use");
var vm = new CilVirtualMachine(module, false);
vm.Invoker = DefaultInvokers.StepIn;
vm.Call(method, Array.Empty<BitVector>());

public interface ITestInterface<out T, in U> {
    public T TestMethod(U u);
}

public class TestClass : ITestInterface<int, long> {
    public static ITestInterface<int, long> Instance = new TestClass();
    
    public int TestMethod(long u) {
        return (int)u;
    }
}

public static class Usage {
    public static int Use() {
        ITestInterface<int, long> tc = new TestClass();
        return tc.TestMethod(44);
    }
}

The current TryFindImplicitImplementationInType doesn't work for this example as the method implementation doesn't have the ReuseSlot flag.

This PR fixes this by resolving the method with the called method's signature if it finds an interface that matches the called method's declaring type (always an interface).

[Washi1337]

Sorry for the late response. Thanks for looking into it and fixing it!