Leave debugStream as null on construction of StandardSyntaxParserToke…

…nManager

* When debugStream is set to Console.Out by default, constructing a StandardQueryParser throws an exception on OSes that do not support Console, such as iOS and Android.
* debugStream can be set later using the setter, if needed.
* See issue apache#936 for details.

src/Lucene.Net.QueryParser/Flexible/Standard/Parser/StandardSyntaxParserTokenManager.cs

@@ -1,4 +1,4 @@
-using Lucene.Net.Support.IO;
+using Lucene.Net.Support.IO;
 using System.Diagnostics.CodeAnalysis;
 using System;
 using System.IO;
@@ -32,7 +32,7 @@ public class StandardSyntaxParserTokenManager /*: StandardSyntaxParserConstants*
     {
         /// <summary>Debug output.</summary>
 #pragma warning disable IDE0052 // Remove unread private members
-        private TextWriter debugStream = Console.Out; // LUCENENET specific - made private, since we already have a setter
+        private TextWriter debugStream; // LUCENENET specific - made private, since we already have a setter
 #pragma warning restore IDE0052 // Remove unread private members
         /// <summary>Set debug output.</summary>
         public void SetDebugStream(TextWriter ds) { debugStream = new SafeTextWriterWrapper(ds); }