Use phone number for grouping when normalized number is null

NORMALIZED_NUMBER may become null when the number isn't able to be
parsed by the library (e.g. pager address). Current implementation
groups multiple numbers with null normalized values into one
result, which confuses users.

Bug: 5040732
Change-Id: I1ad7dfb72dbc5d239aa95a913d35c2d8dfe3167c
3 files changed