Removed some code that I didn't mean to fix (I already submitted this in another PR: https://github.com/assimp/assimp/pull/2450).

code/FBXExportNode.cpp

@@ -253,7 +253,6 @@ void FBX::Node::DumpChildren(
     } else {
         std::ostringstream ss;
         DumpChildrenAscii(ss, indent);
-        if (ss.tellp() > 0)
         s.PutString(ss.str());
     }
 }
@@ -268,7 +267,6 @@ void FBX::Node::End(
     } else {
         std::ostringstream ss;
         EndAscii(ss, indent, has_children);
-        if (ss.tellp() > 0)
         s.PutString(ss.str());
     }
 }