Fix errors in asynchronous example code

Author: sharwell

src/Samples/CSharpCodeSamples/AsynchronousExceptionsExamples.cs

@@ -27,6 +27,7 @@ public void ExceptionDuringTaskExecution()
             try
             {
                 Task myTask = SomeOperationAsync();
+                myTask.Wait();
             }
             catch (AggregateException wrapperEx)
             {

src/Samples/VBCodeSamples/AsynchronousExceptionsExamples.vb

@@ -18,6 +18,7 @@ Public Class AsynchronousExceptionsExamples
         ' #Region ExceptionDuringTaskExecution
         Try
             Dim myTask As Task = SomeOperationAsync()
+            myTask.Wait()
         Catch wrapperEx As AggregateException
             Dim ex = TryCast(wrapperEx.InnerException, ArgumentException)
             If ex Is Nothing Then