Support for native in leg, and start moving native tests to a specific test suite.

frog/leg/compiler.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   Function run;
   Map<int, BailoutInfo> bailouts = null;
   bool allowSpeculativeOptimization = true;
@@ skipping 235 matching lines @@
             }
           }
         }
       }
     }
   }
 
   void runCompiler(Script script) {
     scanBuiltinLibraries();
     mainApp = new LibraryElement(script);
+    native.checkNativeSupport(this, mainApp);
+
     Element element;
     withCurrentElement(mainApp, () {
         scanner.scan(currentElement);
         element = mainApp.find(MAIN);
         if (element === null) cancel('Could not find $MAIN');
       });
     worklist.add(new WorkItem.toCompile(element));
     do {
       while (!worklist.isEmpty()) {
         WorkItem work = worklist.removeLast();
@@ skipping 133 matching lines @@
 
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }