[dart:io] Adds Platform.operatingSystemVersion

pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart

Index: pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart
diff --git a/pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart b/pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart
index 1c6ba822c42df51a2c93e737eed30edbd28788b0..4a61e479889ae060ce922f3baa4e372159c17ede 100644
--- a/pkg/dev_compiler/tool/input_sdk/patch/io_patch.dart
+++ b/pkg/dev_compiler/tool/input_sdk/patch/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");