Fix file test to test for both decomposed and precomposed utf16

tests/standalone/io/file_non_ascii_sync_test.dart

Index: tests/standalone/io/file_non_ascii_sync_test.dart
diff --git a/tests/standalone/io/file_non_ascii_sync_test.dart b/tests/standalone/io/file_non_ascii_sync_test.dart
index d2d56465a9bc1ebcfcfe6bc79120a46c7142309e..170865229b4e045c1c98c405fa5723ef32972353 100644
--- a/tests/standalone/io/file_non_ascii_sync_test.dart
+++ b/tests/standalone/io/file_non_ascii_sync_test.dart
@@ -7,11 +7,19 @@ import 'dart:io';
 main() {
   Directory scriptDir = new File(new Options().script).directorySync();
   var f = new File("${scriptDir.path}/æøå/æøå.dat");
+  // On MacOS you get the decomposed utf8 form of file and directory
+  // names from the system. Therefore, we have to check for both here.
+  var precomposed = 'æøå';
+  var decomposed = new String.fromCharCodes([47, 230, 248, 97, 778]);
   Expect.isTrue(f.existsSync());
   f.createSync();
-  Expect.isTrue(f.directorySync().path.endsWith('æøå'));;
+  var path = f.directorySync().path;
+  Expect.isTrue(f.directorySync().path.endsWith(precomposed) ||
+                f.directorySync().path.endsWith(decomposed));
   Expect.equals(6, f.lengthSync());
   f.lastModifiedSync();
-  Expect.isTrue(f.fullPathSync().endsWith('æøå.dat'));
-  Expect.equals('æøå', f.readAsTextSync());
+  Expect.isTrue(f.fullPathSync().endsWith('${precomposed}.dat') ||
+                f.fullPathSync().endsWith('${decomposed}.dat'));
+  // The contents of the file is precomposed utf8.
+  Expect.equals(precomposed, f.readAsTextSync());
 }