Use native async/await support in pub.

sdk/lib/_internal/pub_generated/lib/src/exit_codes.dart

Index: sdk/lib/_internal/pub_generated/lib/src/exit_codes.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/exit_codes.dart b/sdk/lib/_internal/pub_generated/lib/src/exit_codes.dart
deleted file mode 100644
index ebe8e8deab8e584eb14f1a8156bb00fa404634ce..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/exit_codes.dart
+++ /dev/null
@@ -1,60 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// 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.
-
-/// Exit code constants.
-///
-/// From [the BSD sysexits manpage][manpage]. Not every constant here is used,
-/// even though some of the unused ones may be appropriate for errors
-/// encountered by pub.
-///
-/// [manpage]: http://www.freebsd.org/cgi/man.cgi?query=sysexits
-library pub.exit_codes;
-
-/// The command completely successfully.
-const SUCCESS = 0;
-
-/// The command was used incorrectly.
-const USAGE = 64;
-
-/// The input data was incorrect.
-const DATA = 65;
-
-/// An input file did not exist or was unreadable.
-const NO_INPUT = 66;
-
-/// The user specified did not exist.
-const NO_USER = 67;
-
-/// The host specified did not exist.
-const NO_HOST = 68;
-
-/// A service is unavailable.
-const UNAVAILABLE = 69;
-
-/// An internal software error has been detected.
-const SOFTWARE = 70;
-
-/// An operating system error has been detected.
-const OS = 71;
-
-/// Some system file did not exist or was unreadable.
-const OS_FILE = 72;
-
-/// A user-specified output file cannot be created.
-const CANT_CREATE = 73;
-
-/// An error occurred while doing I/O on some file.
-const IO = 74;
-
-/// Temporary failure, indicating something that is not really an error.
-const TEMP_FAIL = 75;
-
-/// The remote system returned something invalid during a protocol exchange.
-const PROTOCOL = 76;
-
-/// The user did not have sufficient permissions.
-const NO_PERM = 77;
-
-/// Something was unconfigured or mis-configured.
-const CONFIG = 78;