unblock Unix Domain Socket on Dispose on macOS

[wfurt]

fixes #101539
When. Interop.Sys.Disconnect is called on macOS with UDS, it fails and we end up in endless TryUnblockSocket loop.

We could fallback to Shutdown on any error - this is just smallest change to fix the reported issue.,
Lot of the abortive jargon around here really make sense only for TCP imho and I'm n to sure how applicable the logic is to other socket types.

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[wfurt]

Note that the linked issue can also be fixed by adding Shutdown to NamedPipeClientStream's Dispose to make sure everything is written and disconnected. (or we dan perhaps do both)

[tmds]

If there's a regression that causes TryUnblockSocket to break, the test will hang at client.Receive and never time out.

[tmds]

We can do some things like:

runtime/src/libraries/System.Net.Sockets/tests/FunctionalTests/SendReceive/SendReceive.cs

Lines 1079 to 1088 in 5d05361

	await Task.WhenAny(disposeTask, socketOperation)
	.WaitAsync(TimeSpan.FromMilliseconds(TestSettings.PassingTestTimeout));
	await disposeTask
	.WaitAsync(TimeSpan.FromMilliseconds(TestSettings.PassingTestTimeout));
	SocketError? localSocketError = null;
	try
	{
	await socketOperation
	.WaitAsync(TimeSpan.FromMilliseconds(TestSettings.PassingTestTimeout));

[wfurt]

I was thinking about it. However, I think we would notice it and fix it. XUnit now spits out warnings about long running tasks.