[dart:io] Adds Platform.operatingSystemVersion

sdk/lib/_internal/js_runtime/lib/io_patch.dart

Index: sdk/lib/_internal/js_runtime/lib/io_patch.dart
diff --git a/sdk/lib/_internal/js_runtime/lib/io_patch.dart b/sdk/lib/_internal/js_runtime/lib/io_patch.dart
index 773fa5b074cdb02e36be2fb1291aaa5f52b6a664..c62675658119f931e30a12ecd8a86ea632af4660 100644
--- a/sdk/lib/_internal/js_runtime/lib/io_patch.dart
+++ b/sdk/lib/_internal/js_runtime/lib/io_patch.dart
@@ -233,6 +233,11 @@ class _Platform {
     throw new UnsupportedError("Platform._operatingSystem");
   }
 
+  @patch
+  static _operatingSystemVersion() {
+    throw new UnsupportedError("Platform._operatingSystemVersion");
+  }
+
   @patch
   static _localHostname() {
     throw new UnsupportedError("Platform._localHostname");