Consolidate release/deactivation into a single doRelease method.
It needs to check GOOS for backward compatibility, but it's
simpler to keep all the logic in one place.
Change-Id: I242eb084d44d2682f862a8fbf55c410fb8c53358
Reviewed-on: https://go-review.googlesource.com/c/go/+/638580
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>