Handle infinities correctly in ChoiceFormat.

We'd like ChoiceFormat.toPattern to emit a pattern that's parseable
by ChoiceFormat - which means we need an infinity that's parseable by
NumberFormat.parse().

Also, implement the nextDouble / previousDouble public API <sadface/>
in terms of Math.nextAfter and Math.nextUp.

bug: 19149384
Change-Id: Ieb13ee70c212d188ff9fde09463ced8d632f47ab
2 files changed