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

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

 
 class _SVGPathSegCurvetoQuadraticRelJs extends _SVGPathSegJs implements SVGPathSegCurvetoQuadraticRel native "*SVGPathSegCurvetoQuadraticRel" {
 
-  num get x() native "return this.x;";
+  num x;
 
-  void set x(num value) native "this.x = value;";
+  num x1;
 
-  num get x1() native "return this.x1;";
+  num y;
 
-  void set x1(num value) native "this.x1 = value;";
-
-  num get y() native "return this.y;";
-
-  void set y(num value) native "this.y = value;";
-
-  num get y1() native "return this.y1;";
-
-  void set y1(num value) native "this.y1 = value;";
+  num y1;
 }