[dart:io] Adds Platform.localeName

tests/standalone/io/locale_name_test.dart

Index: tests/standalone/io/locale_name_test.dart
diff --git a/tests/standalone/io/locale_name_test.dart b/tests/standalone/io/locale_name_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f488146377dab27c419d6f9e50eaac343e8d1c2e
--- /dev/null
+++ b/tests/standalone/io/locale_name_test.dart
@@ -0,0 +1,14 @@
+import 'dart:io';
+
+import "package:expect/expect.dart";
+
+main() {
+  try {
+    Platform.localeName;
+  } catch (e, s) {
+    Expect.fail("Platform.localeName threw: $e\n$s\n");
+  }
+  Expect.isNotNull(Platform.localeName);
+  Expect.isTrue(Platform.localeName is String);
+  print(Platform.localeName);
+}

[siva, 2017/03/30 17:35:35]

Need status file update for dart2js, analyzer etc. as this test could fail on
those configurations?

[zra, 2017/03/30 17:48:38]

I believe standalone/io tests are already handled correctly in the status files
for these configurations.