Added builtin native call to exit the running vm

runtime/bin/builtin.dart

 // Copyright (c) 2011, 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.
 
 #library("builtin");
 
 void print(arg) {
   _Logger._printString(arg.toString());
 }
 
+void exit(int status) {
+  _Runtime._exit(status);

[Ivan Posva, 2011/10/19 21:57:11]

If called like this:
exit("0");
The VM will run into an assertion, instead you should check that only arguments
with the correct type are forwarded into native code:

void exit(int status) {
  if (status is !int) {
    throw IllegalArgumentException("int status expected");
  }
  _exit(status);
}

_exit(int status) native "_exit";

[rchandia, 2011/10/21 17:29:41]

Done.

+}
+
 class _Logger {
   static void _printString(String s) native "Logger_PrintString";
 }
+
+class _Runtime {

[Ivan Posva, 2011/10/19 21:57:11]

There is no need to add a class as a wrapper here. A top-level native function
_exit would be good enough. Eventually we should do the same thing for Logger,
which only exists due to legacy (all of the Logger functionality has been
gutted.)

[rchandia, 2011/10/21 17:29:41]

Done.

+  static void _exit(int status) native "Runtime_Exit";
+}