Use fields in hidden native DOM classes instead of getters/setters.

client/dom/generated/src/frog/ConvolverNode.dart

 
 class _ConvolverNodeJs extends _AudioNodeJs implements ConvolverNode native "*ConvolverNode" {
 
-  _AudioBufferJs get buffer() native "return this.buffer;";
+  _AudioBufferJs buffer;
 
-  void set buffer(_AudioBufferJs value) native "this.buffer = value;";
-
-  bool get normalize() native "return this.normalize;";
-
-  void set normalize(bool value) native "this.normalize = value;";
+  bool normalize;
 }