[dart:io] Don't close stdin with a socket finalizer

runtime/bin/socket_win.cc

Index: runtime/bin/socket_win.cc
diff --git a/runtime/bin/socket_win.cc b/runtime/bin/socket_win.cc
index a7061f70ff900e6fcaa190c60bb8e50e25cb5061..3b0efe507e10a728d82de5da4e54cf76efcb7d58 100644
--- a/runtime/bin/socket_win.cc
+++ b/runtime/bin/socket_win.cc
@@ -82,6 +82,7 @@ bool Socket::Initialize() {
   return (err == 0);
 }
 
+
 intptr_t Socket::Available(intptr_t fd) {
   ClientSocket* client_socket = reinterpret_cast<ClientSocket*>(fd);
   return client_socket->Available();
@@ -288,7 +289,8 @@ intptr_t Socket::GetStdioHandle(intptr_t num) {
   if (handle == INVALID_HANDLE_VALUE) {
     return -1;
   }
-  StdHandle* std_handle = new StdHandle(handle);
+  StdHandle* std_handle = StdHandle::Stdin(handle);
+  std_handle->Retain();
   std_handle->MarkDoesNotSupportOverlappedIO();
   std_handle->EnsureInitialized(EventHandler::delegate());
   return reinterpret_cast<intptr_t>(std_handle);