New PhysicalAddress.TryParse methods taking span and string

[alnikola]

This PR introduces two new PhysicalAddress.TryParse methods taking span and string as well as adds an PhysicalAddress.Parse overload taking span.
Fixes dotnet/corefx#29780

[alnikola]

/azp run runtime-libraries outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[scalablecory]

Looks good other than this one thing.

[alnikola]

/azp run runtime-libraries outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[iSazonov]

It seems before the PR Parse(null) throw.

For string.Empty we throw too so we could use implicit conversion string->ReadOnlySpan

public static PhysicalAddress Parse(string address) => Parse(address);

[stephentoub]

It seems before the PR Parse(null) throw.

No, it returned None:
https://github.com/dotnet/runtime/pull/1057/files#diff-74838e07dff5967e2e1173264255be64L112-L115

[iSazonov]

I get the exception in PowerShell console (.Net Core 3.1)

[stephentoub]

I don't know what PowerShell is passing there, but passing in null returns None.

using System;
using System.Net.NetworkInformation;

class Program
{
    static void Main()
    {
        Console.WriteLine(PhysicalAddress.Parse(null) == PhysicalAddress.None);
    }
}

outputs:

True

That's the case for .NET Framework as well.

[iSazonov]

@stephentoub Thanks! I will open new issue in PowerShell repo.

[stephentoub]

@alnikola, you merged this with a bunch of failures due to this PR that are causing stack overflow exceptions.

[alnikola]

Sorry for the mistake I was confused by the CI run results. It reported 73 successful checks out of 83 which made me to believe that the code is fine since I didn't do anything platform specific.

[stephentoub]

The build legs and the test legs are separate. Lots of build legs succeeded, but the legs that actually ran the tests failed.