Add frog build target on Windows and change frogium and webdriver components to use frog instead ...

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
===================================================================
--- tools/testing/dart/test_suite.dart	(revision 4004)
+++ tools/testing/dart/test_suite.dart	(working copy)
@@ -947,7 +947,7 @@
         return 'compiler/bin/dartc$suffix';
       case 'frogium':
       case 'webdriver':
-        return 'frog/bin/frogsh$suffix';
+        return 'frog/bin/frog$suffix';
       default:
         throw "Unknown compiler for: ${configuration['component']}";
     }