use OUString for intermediary result in PrepareNumberFormatter
use OUString for intermediary result in PrepareNumberFormatter

Change-Id: I9435d926beb2fd7ebe350f61634673eed7228fbe

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core