Obsolete TestMethodIdentifierProperty constructor and add new constructor with arity parameter

[Youssef1313]

Today, TestMethodIdentifierProperty is declared as:

public sealed record TestMethodIdentifierProperty(string AssemblyFullName, string Namespace, string TypeName, string MethodName, string[] ParameterTypeFullNames, string ReturnTypeFullName) : IProperty

This doesn't have a good place to specify arity. I suggest obsoleting the current constructor (but keeping it for binary compatibility), and add another constructor with int arity parameter.

So, for a method like:

namespace MyNamespace1.MyNamespace2
{
    public class C<T>
    {
         public void M<T2>() { }
    }
}

• Namespace will be MyNamespace1.MyNamespace2
• TypeName will be C`1
• MethodName will be M
• Arity will be 1

[Youssef1313]

FYI @bradwilson @thomhurst

[bradwilson]

We don't have this information in our metadata, since we don't permit overloaded test methods. If this is going to become a hard requirement we'll need to make a breaking change to store it.

[Youssef1313]

@bradwilson It probably won't impact you that much if you just pass 0, but any custom extension that will attempt to read TestMethodIdentifierProperty.MethodArity may not work as expected (No extension that I know of will want to read that today). It's best if the contract of the public API isn't violated though.