Multiple Assignments in a Loop Doesn't Get Emitted

[sebmarkbage]

  var n = __abstract('number', '(3)');
  var i = 0;
  var ii = 0;
  var obj = {}
  do {
    obj[i] = 5;
    obj[ii] = 6;
    obj[i + 1000] = 7;
    i++;
    ii++
  } while (i < n);
  result = obj;

->

(function () {
  var __empty = {};
  var _$0 = 0;
  var _$1 = 0;
  var _2 = {};

  do {
    _2[_$0] = 7;
    var _6 = _$0 + 1;
    var _$2 = _6;
    var _8 = _$1 + 1;
    var _$3 = _8;
    _$0 = _$2;
    _$1 = _$3;
    var _E = 3;
    var _D = _$0 < _E;
    var _$4 = _D;
  } while (_$4);

  result = _2;
})();

When there are multiple unknown properties assigned to in a loop, there should be multiple keys saved so that those statements can be emitted when generating the body.