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.

Review URL: https://codereview.chromium.org/1203533003
3 files changed