Unquarantine CanVeryPhoneNumber test

src/Identity/Specification.Tests/src/UserManagerSpecificationTests.cs

@@ -1471,7 +1471,6 @@ namespace Microsoft.AspNetCore.Identity.Test
         /// </summary>
         /// <returns>Task</returns>
         [Fact]
-        [QuarantinedTest]
         public async Task CanVerifyPhoneNumber()
         {
             var manager = CreateManager();

src/Servers/Kestrel/test/FunctionalTests/Http2/ShutdownTests.cs

@@ -100,7 +100,7 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests.Http2
         }
 
         [ConditionalFact]
-        [QuarantinedTest] // Test still quarantined due to Sockets.Functional tests.
+        [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/21521")] // Test still quarantined due to Sockets.Functional tests.
         public async Task GracefulTurnsAbortiveIfRequestsDoNotFinish()
         {
             var requestStarted = new TaskCompletionSource<object>(TaskCreationOptions.RunContinuationsAsynchronously);