Add an API to access telephonylookup.xml on device

Add core platform APIs / impl code needed to access telephonylookup.xml
on device.

There are now two XML files related to time zones: the common code
between them has been extracted into the package-private XmlUtils class.

Bug: 143451294
Test: atest libcore.libcore.timezone
Change-Id: I7da534f92681ca6d567b09355eebb9c88db74ad2
11 files changed