Fix Idna Test (#72817)

* Fix Idna Test

* Update src/libraries/System.Globalization.Extensions/tests/IdnMapping/Data/Unicode_9_0/Unicode_9_0_IdnaTest.cs

Co-authored-by: Stephen Toub <stoub@microsoft.com>

Co-authored-by: Stephen Toub <stoub@microsoft.com>

src/libraries/System.Globalization.Extensions/tests/IdnMapping/Data/Unicode_9_0/Unicode_9_0_IdnaTest.cs

@@ -26,7 +26,14 @@ public Unicode_9_0_IdnaTest(string line, int lineNumber)
 
             Type = ConvertStringToType(split[0].Trim());
             Source = EscapedToLiteralString(split[1], lineNumber);
-            bool validDomainName = (split.Length != 5 || split[4].Trim() != "NV8");
+            bool validDomainName = (split.Length != 5 || split[4].Trim() != "NV8"); 
+
+            // Server 2019 uses ICU 61.0 whose IDNA does not support the following cases. Ignore these entries there.
+            if (PlatformDetection.IsWindowsServer2019 && Source.EndsWith("\ud802\udf8b\u3002\udb40\udd0a", StringComparison.Ordinal))
+            {
+                Source = "";
+            }
+
             UnicodeResult = new ConformanceIdnaUnicodeTestResult(EscapedToLiteralString(split[2], lineNumber), Source, validDomainName);
             ASCIIResult = new ConformanceIdnaTestResult(EscapedToLiteralString(split[3], lineNumber), UnicodeResult.Value);
             LineNumber = lineNumber;