Move SMS pdu creation fully into the central Phone process.

Previously pdu creation was haphazardly done sometimes by the app and
sometimes centrally by the phone process -- specifically the phone
process did creation for multipart texts.  This change gets rid of the
previous IPC interface for sending raw pdus to SMSDispatch in the
phone process, and instead makes everything work like multipart
messages worked before, namely the structured data is passed and pdu
encoding done centrally.

The motivation for this was the need to ensure that CDMA message id
numbers were strictly monotonic, including across reboots, which
necessitated central state in the form of a system property, which
could in turn only be modified by the phone process.

Hence, this (in part) addresses issue: http://buganizer/issue?id=2075760

Change-Id: I94ca207b6e657c465e8472534704db8646ee277c