remove another old analyzer workaround

lib/runtime/dart/collection.js

 var collection;
 (function(exports) {
   'use strict';
   let _source = Symbol('_source');
   let UnmodifiableListView$ = dart.generic(function(E) {
     class UnmodifiableListView extends _internal.UnmodifiableListBase$(E) {
       UnmodifiableListView(source) {
         this[_source] = source;
         super.UnmodifiableListBase();
       }
@@ skipping 2810 matching lines @@
   let _comparator = Symbol('_comparator');
   let _validKey = Symbol('_validKey');
   let _internal = Symbol('_internal');
   let SplayTreeMap$ = dart.generic(function(K, V) {
     class SplayTreeMap extends _SplayTree$(K) {
       SplayTreeMap(compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
-        this[_comparator] = dart.as(compare == null ? core.Comparable.compare : compare, core.Comparator);
+        this[_comparator] = dart.as(compare == null ? core.Comparable.compare : compare, core.Comparator$(K));
         this[_validKey] = dart.as(isValidKey != null ? isValidKey : v => dart.is(v, K), _Predicate);
         super._SplayTree();
       }
       from(other, compare, isValidKey) {
         if (compare === void 0)
           compare = null;
         if (isValidKey === void 0)
           isValidKey = null;
         let result = new (SplayTreeMap$(K, V))();
         other.forEach((k, v) => {
@@ skipping 2117 matching lines @@
   exports.LinkedHashMapKeyIterable$ = LinkedHashMapKeyIterable$;
   exports.LinkedHashMapKeyIterable = LinkedHashMapKeyIterable;
   exports.LinkedHashMapKeyIterator$ = LinkedHashMapKeyIterator$;
   exports.LinkedHashMapKeyIterator = LinkedHashMapKeyIterator;
   exports.HashSetIterator$ = HashSetIterator$;
   exports.HashSetIterator = HashSetIterator;
   exports.LinkedHashSetCell = LinkedHashSetCell;
   exports.LinkedHashSetIterator$ = LinkedHashSetIterator$;
   exports.LinkedHashSetIterator = LinkedHashSetIterator;
 })(collection || (collection = {}));