fixes for angular hello: String + and disable broken arg parsing

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$(E) {
       ListIterable() {
         super.IterableBase();
       }
       get [core.$iterator]() {
@@ skipping 1828 matching lines @@
     Symbol(name) {
       this[_name] = name;
     }
     unvalidated(name$) {
       this[_name] = name$;
     }
     validated(name) {
       this[_name] = Symbol.validatePublicSymbol(name);
     }
     ['=='](other) {
-      return dart.is(other, Symbol) && dart.notNull(dart.equals(this[_name], dart.dload(other, _name)));
+      return dart.is(other, Symbol) && dart.equals(this[_name], dart.dload(other, _name));
     }
     get hashCode() {
       let arbitraryPrime = 664597;
       return 536870911 & dart.notNull(arbitraryPrime) * dart.notNull(this[_name].hashCode);
     }
     toString() {
       return `Symbol("${this[_name]}")`;
     }
     static getName(symbol) {
       return symbol[_name];
@@ skipping 93 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 = {}));