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

tests/standalone/coverage_test.dart

Index: tests/standalone/coverage_test.dart
diff --git a/tests/standalone/coverage_test.dart b/tests/standalone/coverage_test.dart
index c9a5c5fc152850d932b31ab3ee729e347226fe76..1ec4af4e7982d518e83788b8a3d6d3a3d66950fe 100644
--- a/tests/standalone/coverage_test.dart
+++ b/tests/standalone/coverage_test.dart
@@ -52,7 +52,7 @@ void checkSuccess() {
 void main() {
   // Compute paths for coverage tool and coverage target relative
   // the the path of this script.
-  var scriptPath = dirname(Platform.script);
+  var scriptPath = dirname(Platform.script.toFilePath());
   var toolPath = normalize(join(scriptPath, coverageToolScript));
   targPath = normalize(join(scriptPath, coverageTargetScript));