Change dart:io Platform.script to return a URI. Change all uses of Platform.script to work with th…

tests/standalone/io/process_check_arguments_script.dart

Index: tests/standalone/io/process_check_arguments_script.dart
diff --git a/tests/standalone/io/process_check_arguments_script.dart b/tests/standalone/io/process_check_arguments_script.dart
index 094fba9321c9b30278512cd3764e941b1c04c118..361d11b5ea875e4fea85907e7e627f8c70b5a7c7 100644
--- a/tests/standalone/io/process_check_arguments_script.dart
+++ b/tests/standalone/io/process_check_arguments_script.dart
@@ -22,7 +22,7 @@ class Expect {
 }
 
 main(List<String> arguments) {
-  Expect.isTrue(Platform.script.endsWith(
+  Expect.isTrue(Platform.script.path.endsWith(
       'process_check_arguments_script.dart'));
   var expected_num_args = int.parse(arguments[0]);
   var contains_quote = int.parse(arguments[1]);