sync/atomic: correct result names for Or methods
A few of the new Or methods of the atomic types use "new" as the name
for the result value, but it actually returns the old value. Fix this
by renaming the result values to "old".
Updates #61395.
Change-Id: Ib08db9964f5dfe91929f216d50ff0c9cc891ee49
Reviewed-on: https://go-review.googlesource.com/c/go/+/593855
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>