Hook up the --minify option in dart2js and use it to get rid of unnecessary whitespace inside funct…

lib/compiler/implementation/dart2js.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.
 
 #library('dart2js');
 
 #import('dart:io');
 #import('dart:uri');
 #import('dart:utf');
 
@@ skipping 309 matching lines @@
 
   -h, /h, /?, --help
     Display this message (add -v for information about all options).
 
   -v, --verbose
     Display verbose information.
 
   -p<path>, --package-root=<path>
     Where to find packages, that is, "package:..." imports.
 
+  --minify
+    Generate minified output.
+
   --suppress-warnings
     Do not display any warnings.
 
   --no-colors
     Do not add colors to diagnostic messages.
 
 The following options are only used for compiler development and may
 be removed in a future version:
 
   --output-type=dart
@@ skipping 34 matching lines @@
     } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }