Don't cap num_cores at 32 on 32-bit Windows.

Don't cap num_cores at 32 on 32-bit Windows.

See here for a similar change in Ninja.  Wanna bet they just got Z840s too?
https://github.com/martine/ninja/commit/8c8834acffdc0da0d94119725929acc712c9dfad

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/a760942b3579f7d863345b9d083abdc187266e08

[mtklein_C, 2015-07-01 19:44:37]

mtklein@chromium.org changed reviewers:
+ caryclark@google.com

[mtklein_C, 2015-07-01 19:44:53]

The CQ bit was checked by mtklein@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-01 19:45:02]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1213063011/1

[caryclark, 2015-07-01 19:55:58]

lgtm

[mtklein, 2015-07-01 19:58:27]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2015-07-01 19:58:28]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-07-01 19:58:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1213063011/1

[commit-bot: I haz the power, 2015-07-01 20:06:53]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/a760942b3579f7d863345b9d083abdc187266e08