Remove uses of Options from tools directory. Fix platform_test.

tools/coverage.dart

 // Copyright (c) 2013, 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.
 
 // This test forks a second vm process that runs a dart script as
 // a debug target, single stepping through the entire program, and
 // recording each breakpoint. At the end, a coverage map of the source
 // is printed.
 //
 // Usage: dart coverage.dart [--wire] [--verbose] target_script.dart
@@ skipping 505 matching lines @@
       } else if (char == '"') {
         // Strings can contain braces. Skip their content.
         index = skipString(index);
       }
     }
     return 0;
   }
 }
 
 
-void main() {
-  var options = new Options();
+void main(List<String> arguments) {
   var targetOpts = [ "--debug:0" ];
-  for (String str in options.arguments) {
+  for (String str in arguments) {
     switch (str) {
       case "--verbose":
         showDebuggeeOutput = true;
         break;
       case "--wire":
         verboseWire = true;
         break;
       default:
         targetOpts.add(str);
         break;
     }
   }
 
-  Process.start(options.executable, targetOpts).then((Process process) {
+  Process.start(Platform.executable, targetOpts).then((Process process) {
     process.stdin.close();
     debugger = new Debugger(process);
   });
 }