Increase entityCharacterLimit to 4096

The previous fix to decrease the limit to 1024 breaks the parsing
for some files. The limit is arbitrary, so increasing it to 4096,
which is what some linux distros have been working with.

Change-Id: I131f15278aa99c3f91db2e1ec2d14156ceed4775
Fixes: QTBUG-35459
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: David Faure <david.faure@kdab.com>

src/xml/sax/qxml_p.h

@@ -229,7 +229,7 @@ private:
     // for the DTD currently being parsed.
     static const int dtdRecursionLimit = 2;
     // The maximum amount of characters an entity value may contain, after expansion.
-    static const int entityCharacterLimit = 1024;
+    static const int entityCharacterLimit = 4096;
 
     const QString &string();
     void stringClear();