Disable slicebuffers_success and RunContinueWithStressTestsNoState te…

…st (#48442)

* disable long failing tests

* keeping the skipOncoreclr attribute

src/libraries/System.Net.Sockets/tests/FunctionalTests/SendFile.cs

@@ -202,6 +202,7 @@ public async Task NoFile_Succeeds(bool usePreBuffer, bool usePostBuffer)
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/47734")]
         public async Task SliceBuffers_Success()
         {
             if (!SupportsSendFileSlicing) return; // The overloads under test only support sending byte[] without offset and length

src/libraries/System.Threading.Tasks/tests/Task/TaskContinueWithTests.cs

@@ -42,6 +42,7 @@ public static void RunContinueWithAsyncStateCheckTests()
         // Stresses on multiple continuations from a single antecedent
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
         [SkipOnCoreClr("Test timing out: https://github.com/dotnet/runtime/issues/2271", RuntimeConfiguration.Checked)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/2271")]
         public static void RunContinueWithStressTestsNoState()
         {
             int numIterations = 3;