[dart:io] Remove DART_IO_DISABLED

runtime/bin/io_service_no_ssl.cc

Index: runtime/bin/io_service_no_ssl.cc
diff --git a/runtime/bin/io_service_no_ssl.cc b/runtime/bin/io_service_no_ssl.cc
index 895f01be5222c87a48d91fa8cb200711b0e73c81..fbc0da6a32c746c74ba19e9b3c6c09ba64afa5a8 100644
--- a/runtime/bin/io_service_no_ssl.cc
+++ b/runtime/bin/io_service_no_ssl.cc
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#if !defined(DART_IO_DISABLED) && defined(DART_IO_SECURE_SOCKET_DISABLED)
+#if defined(DART_IO_SECURE_SOCKET_DISABLED)
 
 #include "bin/io_service_no_ssl.h"
 
@@ -69,4 +69,4 @@ void FUNCTION_NAME(IOService_NewServicePort)(Dart_NativeArguments args) {
 }  // namespace bin
 }  // namespace dart
 
-#endif  // !defined(DART_IO_DISABLED) && defined(DART_IO_SECURE_SOCKET_DISABLED)
+#endif  // defined(DART_IO_SECURE_SOCKET_DISABLED)