Make standalone tests not dependent on current working directory.

tests/standalone/io/read_into_const_list_test.dart

Index: tests/standalone/io/read_into_const_list_test.dart
diff --git a/tests/standalone/io/read_into_const_list_test.dart b/tests/standalone/io/read_into_const_list_test.dart
index f010a83916b98def83870d5598016ec5d2bda54c..3eb624a2c71928ebee3be84a0ad7fc503d7317cf 100644
--- a/tests/standalone/io/read_into_const_list_test.dart
+++ b/tests/standalone/io/read_into_const_list_test.dart
@@ -8,8 +8,13 @@
 import "package:expect/expect.dart";
 import "dart:io";
 
-String getFilename(String path) =>
-    new File(path).existsSync() ? path : 'runtime/$path';
+String getFilename(String path) {
+  var testPath = Platform.script.resolve('../../../$path');
+  return new File.fromUri(testPath).existsSync()
+      ? testPath.toFilePath()
+      : Platform.script.resolve('../../../runtime/$path').toFilePath();
+}
+
 
 void main() {
   var a = const [0];