fix: make null reader code suitable to use as return value code

Author: sidorares

lib/compile_text_parser.js

@@ -153,7 +153,7 @@ function readCodeFor(type, charset, encodingExpr, config, options) {
     case Types.DOUBLE:
       return 'packet.parseLengthCodedFloat()';
     case Types.NULL:
-      return 'null; packet.skip(1)';
+      return 'packet.readLengthCodedNumber()';
     case Types.DECIMAL:
     case Types.NEWDECIMAL:
       if (config.decimalNumbers) {