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

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

Index: client/dom/generated/src/frog/BiquadFilterNode.dart
diff --git a/client/dom/generated/src/frog/BiquadFilterNode.dart b/client/dom/generated/src/frog/BiquadFilterNode.dart
index 05eb7bdcc8c71bec6df4d55e2414802914abb734..674a67667fd5bd88f549b38ac1dd834ee730ee7f 100644
--- a/client/dom/generated/src/frog/BiquadFilterNode.dart
+++ b/client/dom/generated/src/frog/BiquadFilterNode.dart
@@ -17,15 +17,13 @@ class _BiquadFilterNodeJs extends _AudioNodeJs implements BiquadFilterNode nativ
 
   static final int PEAKING = 5;
 
-  _AudioParamJs get Q() native "return this.Q;";
+  final _AudioParamJs Q;
 
-  _AudioParamJs get frequency() native "return this.frequency;";
+  final _AudioParamJs frequency;
 
-  _AudioParamJs get gain() native "return this.gain;";
+  final _AudioParamJs gain;
 
-  int get type() native "return this.type;";
-
-  void set type(int value) native "this.type = value;";
+  int type;
 
   void getFrequencyResponse(_Float32ArrayJs frequencyHz, _Float32ArrayJs magResponse, _Float32ArrayJs phaseResponse) native;
 }