fixes private named constructors

lib/runtime/dart/_internal.js

 var _internal;
 (function(exports) {
   'use strict';
   class EfficientLength extends core.Object {
   }
   let ListIterable$ = dart.generic(function(E) {
     class ListIterable extends collection.IterableBase$(E) {
       ListIterable() {
         super.IterableBase();
       }
@@ skipping 328 matching lines @@
           return false;
         }
         this[_current] = this[_iterable].elementAt(this[_index]);
         this[_index] = dart.notNull(this[_index]) + 1;
         return true;
       }
     }
     return ListIterator;
   });
   let ListIterator = ListIterator$(dart.dynamic);
+  let _ = Symbol('_');
   let _f = Symbol('_f');
-  let _ = Symbol('_');
   let MappedIterable$ = dart.generic(function(S, T) {
     class MappedIterable extends collection.IterableBase$(T) {
       MappedIterable(iterable, func) {
         if (dart.is(iterable, EfficientLength)) {
           return new EfficientLengthMappedIterable(iterable, func);
         }
-        return new MappedIterable._(dart.as(iterable, core.Iterable$(S)), func);
+        return new MappedIterable[_](dart.as(iterable, core.Iterable$(S)), func);
       }
-      MappedIterable$_(iterable$, f$) {
+      [_](iterable$, f$) {
         this[_iterable] = iterable$;
         this[_f] = f$;
         super.IterableBase();
       }
       get iterator() {
         return new MappedIterator(this[_iterable].iterator, this[_f]);
       }
       get length() {
         return this[_iterable].length;
       }
@@ skipping 13 matching lines @@
         return this[_f](this[_iterable].elementAt(index));
       }
     }
     dart.defineNamedConstructor(MappedIterable, _);
     return MappedIterable;
   });
   let MappedIterable = MappedIterable$(dart.dynamic, dart.dynamic);
   let EfficientLengthMappedIterable$ = dart.generic(function(S, T) {
     class EfficientLengthMappedIterable extends MappedIterable$(S, T) {
       EfficientLengthMappedIterable(iterable, func) {
-        super.MappedIterable$_(dart.as(iterable, core.Iterable$(S)), func);
+        super[_](dart.as(iterable, core.Iterable$(S)), func);
       }
     }
     return EfficientLengthMappedIterable;
   });
   let EfficientLengthMappedIterable = EfficientLengthMappedIterable$(dart.dynamic, dart.dynamic);
   let _iterator = Symbol('_iterator');
   let MappedIterator$ = dart.generic(function(S, T) {
     class MappedIterator extends core.Iterator$(T) {
       MappedIterator(iterator$, f$) {
         this[_iterator] = iterator$;
@@ skipping 120 matching lines @@
   let _takeCount = Symbol('_takeCount');
   let TakeIterable$ = dart.generic(function(E) {
     class TakeIterable extends collection.IterableBase$(E) {
       TakeIterable(iterable, takeCount) {
         if (dart.notNull(!(typeof takeCount == 'number')) || dart.notNull(takeCount) < 0) {
           throw new core.ArgumentError(takeCount);
         }
         if (dart.is(iterable, EfficientLength)) {
           return new EfficientLengthTakeIterable(iterable, takeCount);
         }
-        return new TakeIterable._(iterable, takeCount);
+        return new TakeIterable[_](iterable, takeCount);
       }
-      TakeIterable$_(iterable$, takeCount$) {
+      [_](iterable$, takeCount$) {
         this[_iterable] = iterable$;
         this[_takeCount] = takeCount$;
         super.IterableBase();
       }
       get iterator() {
         return new TakeIterator(this[_iterable].iterator, this[_takeCount]);
       }
     }
     dart.defineNamedConstructor(TakeIterable, _);
     return TakeIterable;
   });
   let TakeIterable = TakeIterable$(dart.dynamic);
   let EfficientLengthTakeIterable$ = dart.generic(function(E) {
     class EfficientLengthTakeIterable extends TakeIterable$(E) {
       EfficientLengthTakeIterable(iterable, takeCount) {
-        super.TakeIterable$_(iterable, takeCount);
+        super[_](iterable, takeCount);
       }
       get length() {
         let iterableLength = this[_iterable].length;
         if (dart.notNull(iterableLength) > dart.notNull(this[_takeCount]))
           return this[_takeCount];
         return iterableLength;
       }
     }
     return EfficientLengthTakeIterable;
   });
@@ skipping 65 matching lines @@
     return TakeWhileIterator;
   });
   let TakeWhileIterator = TakeWhileIterator$(dart.dynamic);
   let _skipCount = Symbol('_skipCount');
   let SkipIterable$ = dart.generic(function(E) {
     class SkipIterable extends collection.IterableBase$(E) {
       SkipIterable(iterable, count) {
         if (dart.is(iterable, EfficientLength)) {
           return new EfficientLengthSkipIterable(iterable, count);
         }
-        return new SkipIterable._(iterable, count);
+        return new SkipIterable[_](iterable, count);
       }
-      SkipIterable$_(iterable$, skipCount$) {
+      [_](iterable$, skipCount$) {
         this[_iterable] = iterable$;
         this[_skipCount] = skipCount$;
         super.IterableBase();
         if (!(typeof this[_skipCount] == 'number')) {
           throw new core.ArgumentError.value(this[_skipCount], "count is not an integer");
         }
         core.RangeError.checkNotNegative(this[_skipCount], "count");
       }
       skip(count) {
         if (!(typeof this[_skipCount] == 'number')) {
           throw new core.ArgumentError.value(this[_skipCount], "count is not an integer");
         }
         core.RangeError.checkNotNegative(this[_skipCount], "count");
-        return new SkipIterable._(this[_iterable], dart.notNull(this[_skipCount]) + dart.notNull(count));
+        return new SkipIterable[_](this[_iterable], dart.notNull(this[_skipCount]) + dart.notNull(count));
       }
       get iterator() {
         return new SkipIterator(this[_iterable].iterator, this[_skipCount]);
       }
     }
     dart.defineNamedConstructor(SkipIterable, _);
     return SkipIterable;
   });
   let SkipIterable = SkipIterable$(dart.dynamic);
   let EfficientLengthSkipIterable$ = dart.generic(function(E) {
     class EfficientLengthSkipIterable extends SkipIterable$(E) {
       EfficientLengthSkipIterable(iterable, skipCount) {
-        super.SkipIterable$_(iterable, skipCount);
+        super[_](iterable, skipCount);
       }
       get length() {
         let length = dart.notNull(this[_iterable].length) - dart.notNull(this[_skipCount]);
         if (dart.notNull(length) >= 0)
           return length;
         return 0;
       }
     }
     return EfficientLengthSkipIterable;
   });
@@ skipping 1088 matching lines @@
         Sort[_doSort](a, less, great, compare);
       }
     }
   }
   Sort._INSERTION_SORT_THRESHOLD = 32;
   let _name = Symbol('_name');
   class Symbol extends core.Object {
     Symbol(name) {
       this[_name] = name;
     }
-    Symbol$unvalidated(name$) {
+    unvalidated(name$) {
       this[_name] = name$;
     }
-    Symbol$validated(name) {
+    validated(name) {
       this[_name] = Symbol.validatePublicSymbol(name);
     }
     ['=='](other) {
       return dart.notNull(dart.is(other, Symbol)) && dart.notNull(dart.equals(this[_name], dart.dload(other, '_name')));
     }
     get hashCode() {
       let arbitraryPrime = 664597;
       return 536870911 & dart.notNull(arbitraryPrime) * dart.notNull(this[_name].hashCode);
     }
     toString() {
@@ skipping 96 matching lines @@
   exports.ReversedListIterable$ = ReversedListIterable$;
   exports.UnmodifiableListError = UnmodifiableListError;
   exports.NonGrowableListError = NonGrowableListError;
   exports.makeListFixedLength = makeListFixedLength;
   exports.Lists = Lists;
   exports.printToConsole = printToConsole;
   exports.Sort = Sort;
   exports.Symbol = Symbol;
   exports.POWERS_OF_TEN = POWERS_OF_TEN;
 })(_internal || (_internal = {}));