Fix WinHttp StreamingTest backward compat version (#104722)

* Add WS2022 to OsSupport check for Bidirectional Streaming

* Enable the disabled test

* Add helper property to PlatformDetection.Windows for WS2022

* Use helper property for WS2022

Author: liveans

src/libraries/Common/tests/TestUtilities/System/PlatformDetection.Windows.cs

@@ -25,6 +25,7 @@ public static partial class PlatformDetection
         public static bool IsWindows8xOrLater => IsWindowsVersionOrLater(6, 2);
         public static bool IsWindows10OrLater => IsWindowsVersionOrLater(10, 0);
         public static bool IsWindowsServer2019 => IsWindows && IsNotWindowsNanoServer && GetWindowsVersion() == 10 && GetWindowsMinorVersion() == 0 && GetWindowsBuildVersion() == 17763;
+        public static bool IsWindowsServer2022 => IsWindows && IsNotWindowsNanoServer && GetWindowsVersion() == 10 && GetWindowsMinorVersion() == 0 && GetWindowsBuildVersion() == 20348;
         public static bool IsWindowsNanoServer => IsWindows && (IsNotWindowsIoTCore && GetWindowsInstallationType().Equals("Nano Server", StringComparison.OrdinalIgnoreCase));
         public static bool IsWindowsServerCore => IsWindows && GetWindowsInstallationType().Equals("Server Core", StringComparison.OrdinalIgnoreCase);
         public static int WindowsVersion => IsWindows ? (int)GetWindowsVersion() : -1;

src/libraries/System.Net.Http.WinHttpHandler/tests/FunctionalTests/BidirectionStreamingTest.cs

@@ -22,7 +22,9 @@ public BidirectionStreamingTest(ITestOutputHelper output) : base(output)
 
         // Build number suggested by the WinHttp team.
         // It can be reduced if bidirectional streaming is backported.
-        public static bool OsSupportsWinHttpBidirectionalStreaming => Environment.OSVersion.Version >= new Version(10, 0, 22357, 0);
+        public static bool OsSupportsWinHttpBidirectionalStreaming => Environment.OSVersion.Version >= new Version(10, 0, 22357, 0)
+            || PlatformDetection.IsWindowsServer2022; // This is required
+                                                                              // because WINHTTP_FLAG_AUTOMATIC_CHUNKING is backported to WS2022.
 
         public static bool TestsEnabled => OsSupportsWinHttpBidirectionalStreaming && PlatformDetection.SupportsAlpn;
 
@@ -324,7 +326,6 @@ async Task RunServer()
         }
 
         [ConditionalFact(nameof(TestsBackwardsCompatibilityEnabled))]
-        [ActiveIssue("https://github.com/dotnet/runtime/issues/103754")]
         public async Task BackwardsCompatibility_DowngradeToHttp11()
         {
             TaskCompletionSource<object> completeStreamTcs = new TaskCompletionSource<object>(TaskCreationOptions.RunContinuationsAsynchronously);