Disable SocketsHttpHandlerTest_Http2.InboundWindowSize_Exceeded_Throw (…

…dotnet/corefx#38722)

Test is consistently failing in CI.

Commit migrated from dotnet/corefx@468355e

src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http2.cs

@@ -1598,6 +1598,7 @@ public async Task Http2GetAsync_TrailigPseudo_Throw()
         }
 
         [Fact]
+        [ActiveIssue(38708)]
         public async Task InboundWindowSize_Exceeded_Throw()
         {
             var semaphore = new SemaphoreSlim(0);