Made assert a keyword.

lib/compiler/implementation/scanner/keyword.dart

Index: lib/compiler/implementation/scanner/keyword.dart
diff --git a/lib/compiler/implementation/scanner/keyword.dart b/lib/compiler/implementation/scanner/keyword.dart
index 1d5319ba27dd3abefb7979aaa030bd2c74e31fe0..4bebb37a651a794d0cf9ddfc901b4b161f54a285 100644
--- a/lib/compiler/implementation/scanner/keyword.dart
+++ b/lib/compiler/implementation/scanner/keyword.dart
@@ -7,6 +7,7 @@
  */
 class Keyword implements SourceString {
   static const List<Keyword> values = const <Keyword> [
+      const Keyword("assert"),
       const Keyword("break"),
       const Keyword("case"),
       const Keyword("catch"),
@@ -39,7 +40,6 @@ class Keyword implements SourceString {
 
       const Keyword("abstract", isBuiltIn: true),
       const Keyword("as", info: AS_INFO, isBuiltIn: true),
-      const Keyword("assert", isBuiltIn: true),
       const Keyword("external", isBuiltIn: true),
       const Keyword("factory", isBuiltIn: true),
       const Keyword("get", isBuiltIn: true),