Clarify iOS flush-to-zero status.

Clarify iOS flush-to-zero status.

Modern processors support flush-to-zero and denormalized-are-zero
for floating point operations (with ARM NEON unable to disable them).
However, iOS on ARM is the only current system which defaults
processes to using both all the time. However, this is only iOS on
ARM, iOS on x86 (the simulator) does not. Correctly defining this
allows the math tests to run error free in the simulator.

Committed: https://skia.googlesource.com/skia/+/4760f32f2a68acdcfee53eae98bbdabb19238e8d

[bungeman-skia, 2015-06-22 20:10:10]

bungeman@google.com changed reviewers:
+ mtklein@google.com, reed@google.com

[bungeman-skia, 2015-06-22 21:42:01]

The CQ bit was checked by bungeman@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-22 21:42:29]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1203533003/40001

[commit-bot: I haz the power, 2015-06-22 21:48:26]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-22 21:48:28]

Dry run: This issue passed the CQ dry run.

[mtklein, 2015-06-24 20:02:51]

The CQ bit was checked by mtklein@google.com

[mtklein, 2015-06-24 20:02:52]

lgtm

[commit-bot: I haz the power, 2015-06-24 20:03:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1203533003/40001

[commit-bot: I haz the power, 2015-06-24 20:08:56]

Committed patchset #3 (id:40001) as
https://skia.googlesource.com/skia/+/4760f32f2a68acdcfee53eae98bbdabb19238e8d