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

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$(E) {
       UnmodifiableListView(source) {
         this[_source] = source;
         super.UnmodifiableListBase();
       }
@@ skipping 224 matching lines @@
         }
         return true;
       }
       [core.$join](separator) {
         if (separator === void 0)
           separator = "";
         let iterator = this[core.$iterator];
         if (!dart.notNull(iterator.moveNext()))
           return "";
         let buffer = new core.StringBuffer();
-        if (dart.notNull(separator == null) || dart.notNull(separator == "")) {
+        if (separator == null || separator == "") {
           do {
             buffer.write(`${iterator.current}`);
           } while (iterator.moveNext());
         } else {
           buffer.write(`${iterator.current}`);
           while (iterator.moveNext()) {
             buffer.write(separator);
             buffer.write(`${iterator.current}`);
           }
         }
@@ skipping 225 matching lines @@
         }
         return true;
       }
       [core.$join](separator) {
         if (separator === void 0)
           separator = "";
         let iterator = this[core.$iterator];
         if (!dart.notNull(iterator.moveNext()))
           return "";
         let buffer = new core.StringBuffer();
-        if (dart.notNull(separator == null) || dart.notNull(separator == "")) {
+        if (separator == null || separator == "") {
           do {
             buffer.write(`${iterator.current}`);
           } while (iterator.moveNext());
         } else {
           buffer.write(`${iterator.current}`);
           while (iterator.moveNext()) {
             buffer.write(separator);
             buffer.write(`${iterator.current}`);
           }
         }
@@ skipping 180 matching lines @@
         }
         return true;
       }
       [core.$join](separator) {
         if (separator === void 0)
           separator = "";
         let iterator = this[core.$iterator];
         if (!dart.notNull(iterator.moveNext()))
           return "";
         let buffer = new core.StringBuffer();
-        if (dart.notNull(separator == null) || dart.notNull(separator == "")) {
+        if (separator == null || separator == "") {
           do {
             buffer.write(`${iterator.current}`);
           } while (iterator.moveNext());
         } else {
           buffer.write(`${iterator.current}`);
           while (iterator.moveNext()) {
             buffer.write(separator);
             buffer.write(`${iterator.current}`);
           }
         }
@@ skipping 123 matching lines @@
       }
       toString() {
         return IterableBase.iterableToShortString(this, '(', ')');
       }
       static iterableToShortString(iterable, leftDelimiter, rightDelimiter) {
         if (leftDelimiter === void 0)
           leftDelimiter = '(';
         if (rightDelimiter === void 0)
           rightDelimiter = ')';
         if (IterableBase[_isToStringVisiting](iterable)) {
-          if (dart.notNull(leftDelimiter == "(") && dart.notNull(rightDelimiter == ")")) {
+          if (leftDelimiter == "(" && rightDelimiter == ")") {
             return "(...)";
           }
           return `${leftDelimiter}...${rightDelimiter}`;
         }
         let parts = new core.List.from([]);
         IterableBase[_toStringVisiting][core.$add](iterable);
         try {
           IterableBase[_iterablePartsToStrings](iterable, parts);
         } finally {
           dart.assert(core.identical(IterableBase[_toStringVisiting][core.$last], iterable));
@@ skipping 4112 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 = {}));