Add some race-detector tests

Add some race-detector tests

The impl/memory one is fine, but the txnBuf one is currently failing.

R=dnj@chromium.org, estaab@chromium.org, vadimsh@chromium.org
BUG=

Committed: https://github.com/luci/gae/commit/013f2ca6914c1a8f3fc7e62c29a432cdeffecca5

[dnj, 2015-11-10 00:20:20]

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
File impl/memory/race_test.go (right):

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
impl/memory/race_test.go:19: value := new(int64)
nit: int64(0), use &value elsewhere.

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
impl/memory/race_test.go:55: atomic.AddInt64(value, 1)
This may break on 32-bit systems b/c not allocated as the first member of a
struct; why not just use int32's here and avoid the issue?

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
impl/memory/race_test.go:75: num := new(int64)
int64(0)

[iannucci, 2015-11-11 18:13:58]

ptal

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
File impl/memory/race_test.go (right):

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
impl/memory/race_test.go:19: value := new(int64)
On 2015/11/10 at 00:20:20, dnj wrote:
> nit: int64(0), use &value elsewhere.

*shrug*

https://chromiumcodereview.appspot.com/1437553002/diff/1/impl/memory/race_tes...
impl/memory/race_test.go:55: atomic.AddInt64(value, 1)
On 2015/11/10 at 00:20:20, dnj wrote:
> This may break on 32-bit systems b/c not allocated as the first member of a
struct; why not just use int32's here and avoid the issue?

it's allocated so it's fine

[dnj, 2015-11-11 18:14:53]

lgtm

[iannucci, 2015-11-11 18:15:06]

The CQ bit was checked by iannucci@chromium.org

[commit-bot: I haz the power, 2015-11-11 18:15:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1437553002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1437553002/20001

[commit-bot: I haz the power, 2015-11-11 18:19:26]

Committed patchset #2 (id:20001) as
https://github.com/luci/gae/commit/013f2ca6914c1a8f3fc7e62c29a432cdeffecca5