sync/atomic: don't run 64-bit uintptr tests on 32-bit systems
The tests don't work on big-endian systems. This change handles more
of the tests added in CL 381317 like the other existing tests.
Fixes #52723
Change-Id: Ie9e048e75dbe0b5aca61b51cd0c50d7d878ff6d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/404495
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Bryan Mills <bcmills@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>