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

frog/leg/ssa/codegen.dart

Index: frog/leg/ssa/codegen.dart
===================================================================
--- frog/leg/ssa/codegen.dart	(revision 4354)
+++ frog/leg/ssa/codegen.dart	(working copy)
@@ -536,7 +536,7 @@
       }
       code = code.replaceAll('\$$i', name);
     }
-    buffer.add('($code)');
+    buffer.add('$code');

[floitsch, 2012/02/19 00:59:43]

Afair we do 'generateAtUseSite' for HForeigns. Unless you can guarantee that
there will never be a precedence issue I vote strongly in favor of keeping the
parenthesis.
As said before HForeign should be expressions.

[ngeoffray, 2012/02/20 17:00:02]

Added a test generateAtUseSite to know if we need to add parens.

   }
 
   visitForeignNew(HForeignNew node) {