Support multiple scripts for digits and decimal symbols per locale

CLDR supports digits and decimal symbols (such as decimal point) in multiple scripts, as number systems, per locale. For example, ar.xml of CLDR has 2 number systems, "arab" and "latn".

On the other hand, java.text.DecimalFormatSymbols supports a single set of digits and symbols per locale. This needs to be enhanced in order to support CLDR data.