revert changes in async chain tests

I have not seen the test description before

src/PipelineNet.Tests/ChainsOfResponsibility/AsyncResponsibilityChainTests.cs

@@ -170,14 +170,15 @@ public void Chain_AddTypeThatIsNotAMiddleware_ThrowsException()
         /// Try to generate a deadlock in synchronous middleware.
         /// </summary>
         [Fact]
-        public async Task Execute_SynchronousChainOfResponsibility_SuccessfullyExecute()
+        public void Execute_SynchronousChainOfResponsibility_SuccessfullyExecute()
         {
             var responsibilityChain = new AsyncResponsibilityChain<string, string>(new ActivatorMiddlewareResolver())
                 .Chain<SyncReplaceNewLineMiddleware>()
                 .Chain<SyncTrimMiddleware>()
                 .Finally(input => Task.FromResult(input));
 
-            var result = await responsibilityChain.Execute("  Test\nwith spaces\n and new lines \n ");
+            var resultTask = responsibilityChain.Execute("  Test\nwith spaces\n and new lines \n ");
+            var result = resultTask.Result;
 
             Assert.Equal("Test with spaces  and new lines", result);
         }