windows: drop go version tags for unsupported versions

go.mod specifies go 1.18. Drop go1.n version tags for older, unsupported
versions.

Change-Id: I7a23a9f4ba558999ac417b7b4647fa1061d69c06
Reviewed-on: https://go-review.googlesource.com/c/sys/+/566038
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

Author: tklauser

windows/aliases.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build windows && go1.9
+//go:build windows
 
 package windows