fix fields that override getters/setters

lib/runtime/dart/convert.js

 var convert;
 (function(exports) {
   'use strict';
   let ASCII = new AsciiCodec();
   let _ASCII_MASK = 127;
   let _allowInvalid = Symbol('_allowInvalid');
   let _nameToEncoding = Symbol('_nameToEncoding');
   let Codec$ = dart.generic(function(S, T) {
     class Codec extends core.Object {
       Codec() {
@@ skipping 316 matching lines @@
       this[_sink] = sink;
       super.ByteConversionSinkBase();
     }
     add(chunk) {
       return this[_sink].add(chunk);
     }
     close() {
       return this[_sink].close();
     }
   }
+  let _INITIAL_BUFFER_SIZE = Symbol('_INITIAL_BUFFER_SIZE');
   let _buffer = Symbol('_buffer');
-  let _INITIAL_BUFFER_SIZE = Symbol('_INITIAL_BUFFER_SIZE');
   let _callback = Symbol('_callback');
   let _bufferIndex = Symbol('_bufferIndex');
   let _roundToPowerOf2 = Symbol('_roundToPowerOf2');
   class _ByteCallbackSink extends ByteConversionSinkBase {
     _ByteCallbackSink(callback) {
       this[_buffer] = new typed_data.Uint8List(_ByteCallbackSink[_INITIAL_BUFFER_SIZE]);
       this[_callback] = callback;
       this[_bufferIndex] = 0;
       super.ByteConversionSinkBase();
     }
@@ skipping 2088 matching lines @@
   exports.LineSplitter = LineSplitter;
   exports.StringConversionSink = StringConversionSink;
   exports.ClosableStringSink = ClosableStringSink;
   exports.UNICODE_REPLACEMENT_CHARACTER_RUNE = UNICODE_REPLACEMENT_CHARACTER_RUNE;
   exports.UNICODE_BOM_CHARACTER_RUNE = UNICODE_BOM_CHARACTER_RUNE;
   exports.UTF8 = UTF8;
   exports.Utf8Codec = Utf8Codec;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
 })(convert || (convert = {}));