Unquarantine tests (#39659)

Author: HaoK

src/Servers/HttpSys/test/FunctionalTests/Listener/RequestBodyTests.cs

@@ -17,7 +17,6 @@ namespace Microsoft.AspNetCore.Server.HttpSys.Listener;
 public class RequestBodyTests
 {
     [ConditionalFact]
-    [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/27399")]
     public async Task RequestBody_SyncReadDisabledByDefault_WorksWhenEnabled()
     {
         string address;

src/Servers/IIS/IIS/test/Common.FunctionalTests/RequestResponseTests.cs

@@ -156,12 +156,10 @@ public async Task PassesThroughCompressionInProcess()
     }
 
     [ConditionalFact]
-    [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/26294")]
-    [SkipNonHelix("This test takes 5 minutes to run")]
     public async Task ReadAndWriteSynchronously()
     {
         var content = new StringContent(new string('a', 100000));
-        for (int i = 0; i < 500; i++)
+        for (int i = 0; i < 50; i++)
         {
             var response = await _fixture.Client.PostAsync("ReadAndWriteSynchronously", content);
             var responseText = await response.Content.ReadAsStringAsync();

src/Servers/IIS/IIS/test/IIS.Tests/ClientDisconnectTests.cs

@@ -225,7 +225,6 @@ public async Task ReaderThrowsCanceledException()
     }
 
     [ConditionalFact]
-    [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/27400")]
     public async Task ReaderThrowsResetExceptionOnInvalidBody()
     {
         var requestStartedCompletionSource = CreateTaskCompletionSource();