Convert Arabic phone numbers to ASCII when sending SMS.

Modify PhoneNumberUtils to automatically convert non-ASCII digits,
such as Arabic-Indic numbers, CJK full-width digits, etc., to ASCII
in normalizeNumber(), extractNetworkPortion(), and stripSeparators().

This enables the SMS application to support sending SMS's to phone
numbers written with Arabic, or other non-ASCII digits. The number will
be converted to ASCII digits and formatted for the user according to the
country formatting rules.

Bug: 5615791
Change-Id: I42039285db5795b1dda22e4251f54af302e27f13

Signed-off-by: Jake Hamby <jhamby@google.com>