Fix PerMill sign in DecimalFormatSymbols - part 2

- LocaleData.perMill is now a string type. Change layoutlib to adopt
this change.
- Layoutlib should only used by IDE, and it shouldn't break
any device build

Bug: 67034519
Test: m
Change-Id: Iaa263cf40eb2185e9677fe5d2bd8682a477216dc
1 file changed