Revert "Change dart:io Platform.script to return a Uri."

sdk/lib/io/platform_impl.dart

Index: sdk/lib/io/platform_impl.dart
diff --git a/sdk/lib/io/platform_impl.dart b/sdk/lib/io/platform_impl.dart
index 3e018a0e7b669bffa3d8a77869c79361f30ab12c..56a586916d04af66c7179bebb6b0398bb6882291 100644
--- a/sdk/lib/io/platform_impl.dart
+++ b/sdk/lib/io/platform_impl.dart
@@ -18,18 +18,6 @@ class _Platform {
   static int get numberOfProcessors => _numberOfProcessors();
   static String get pathSeparator => _pathSeparator();
   static String get operatingSystem => _operatingSystem();
-  static Uri script = _script();
-  static Uri _script() {
-    // The embedder (Dart executable) creates the Platform._nativeScript field.
-    var s = Platform._nativeScript;
-    if (s.startsWith('http:') ||
-        s.startsWith('https:') ||
-        s.startsWith('file:')) {
-      return Uri.parse(s);
-    } else {
-      return new Uri.file(s);
-    }
-  }
 
   static String get localHostname {
     var result = _localHostname();