Harden and re-enable DualMode socket tests

[antonfirsov]

Fixes#1481.
Fixes#79820.

Throwing DisableParallelization at all tests in DualModeSocketTest increased the total execution time of those tests by approximately 1 minute on my Windows machine, so I decided to go with a more sophisticated approach.

• UDP tests are moved to a non-parallel collection, since there is no way to prevent parallel UDP tests from intercepting each other's packets. This only increases the execution time by ~2 seconds.
• TCP interferences are prevented by a utility PortBlocker, which creates and binds a "shadow" socket of the opposite address family to prevent sockets in parallel tests to bind to the same port.
• Accept and SendTo tests are refactored to use SocketTestHelperBase<T>, reducing duplicate code.

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Issue Details

---

Fixes #1481.
Fixes #21853.

Dropping DisableParallelization at all tests in DualModeSocketTest increased the total execution time of those tests by approximately 1 minute on my Windows machine, so I decided to go with a more sophisticated approach.

• UDP tests are moved to a non-parallel collection, since there is no way to prevent parallel UDP tests from intercepting each other's packets. This only increases the execution time by ~2 seconds.
• TCP interferences are prevented by a utility PortBlocker, which creates and binds a "shadow" socket of the opposite address family to prevent sockets in parallel tests to bind to the same port.
• Accept and SendTo tests are refactored to use SocketTestHelperBase<T>, reducing duplicate code.

Author:	antonfirsov
Assignees:	-
Labels:	area-System.Net.Sockets
Milestone:	-

[liveans]

/azp run runtime-libraries-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[liveans]

LGTM

[antonfirsov]

/azp run runtime-libraries-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[antonfirsov]

/azp run runtime

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[antonfirsov]

@wfurt do you want to take a look, or should I go ahead and merge this?

[wfurt]

LGTM. I would probably go with disabled parallelization but I'm fine with the helper if you feel it would stabilize the test. Time will tell and keeping the test disable does not provide any benefits.

[ManickaP]

I think that some of the re-enabled / shuffled tests are failing on extra platform pipeline:
https://dev.azure.com/dnceng-public/public/_build/results?buildId=165856&view=ms.vss-test-web.build-test-results-tab&runId=3369863&resultId=168462&paneView=debug
https://helixre107v0xdeko0k025g8.blob.core.windows.net/dotnet-runtime-refs-pull-81481-merge-79b8ca868c0d49858f/System.Net.Sockets.Tests/3/testResults.xml?helixlogtype=result

<test name="System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom.ReceiveMessageFromAsyncV4BoundToSpecificV6_NotReceived" type="System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom" method="ReceiveMessageFromAsyncV4BoundToSpecificV6_NotReceived" time="0.0168523" result="Fail">
<traits>
<trait name="IPv4" value="true"/>
<trait name="IPv6" value="true"/>
</traits>
<failure exception-type="Xunit.Sdk.ThrowsException">
<message>
Assert.Throws() Failure\nExpected: typeof(System.TimeoutException)\nActual: typeof(System.ArgumentException): The supplied EndPoint of AddressFamily InterNetwork is not valid for this Socket, use InterNetworkV6 instead. (Parameter 'e')\n---- System.ArgumentException : The supplied EndPoint of AddressFamily InterNetwork is not valid for this Socket, use InterNetworkV6 instead. (Parameter 'e')
</message>
<stack-trace>
at System.Net.Sockets.Socket.ReceiveMessageFromAsync(SocketAsyncEventArgs e, CancellationToken cancellationToken) at System.Net.Sockets.Socket.ReceiveMessageFromAsync(SocketAsyncEventArgs e) at System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom.ReceiveMessageFromAsync_Helper(IPAddress listenOn, IPAddress connectTo, Boolean expectedToTimeout) in /_/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs:line 1666 at System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom.<ReceiveMessageFromAsyncV4BoundToSpecificV6_NotReceived>b__39_0() in /_/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs:line 1613 ----- Inner Stack Trace ----- at System.Net.Sockets.Socket.ReceiveMessageFromAsync(SocketAsyncEventArgs e, CancellationToken cancellationToken) at System.Net.Sockets.Socket.ReceiveMessageFromAsync(SocketAsyncEventArgs e) at System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom.ReceiveMessageFromAsync_Helper(IPAddress listenOn, IPAddress connectTo, Boolean expectedToTimeout) in /_/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs:line 1666 at System.Net.Sockets.Tests.DualModeConnectionlessReceiveMessageFrom.<ReceiveMessageFromAsyncV4BoundToSpecificV6_NotReceived>b__39_0() in /_/src/libraries/System.Net.Sockets/tests/FunctionalTests/DualModeSocketTest.cs:line 1613
</stack-trace>
</failure>
</test>

cc: @antonfirsov