Tests: Guard text writes

StackExchange.Redis.Tests/Helpers/TextWriterOutputHelper.cs

@@ -13,11 +13,20 @@ public class TextWriterOutputHelper : TextWriter
         public TextWriterOutputHelper(ITestOutputHelper outputHelper) => Output = outputHelper;
 
         public override void WriteLine(string value)
+        {
+            try
             {
                 base.Write(DateTime.UtcNow.ToString("HH:mm:ss.fff"));
                 base.Write(": ");
                 base.WriteLine(value);
             }
+            catch (Exception ex)
+            {
+                Console.Write("Attempted to write: ");
+                Console.WriteLine(value);
+                Console.WriteLine(ex);
+            }
+        }
 
         public override void Write(char value)
         {