Provide a new command line for host tests

This adds a new cmd verb for time_zone_detector that reports whether
telephony time zone detection is supported. This enables a host side CTS
test to properly determine expected behavior on non-telephony devices
like Android Auto.

Bug: 187907947
Test: See associated cts change
Change-Id: Ie118459c704112a259d38cb246882f11f8c5dee0