Switch telephony to use system API proxies

Switch telephony code over to using System API proxies for in-process
time zone lookup calls.

This test modifies TestApplication so that the test environment behaves
like the real environment and so that tests can make the necessary
calls. See the comments there for details.

Bug: 139091367
Test: boot / successful time zone detection in the UK.
Test: "atest FrameworksTelephonyTests" with no exceptions from tz tests
Merged-In: I668be5204547a2606dd314cff73bd0e9ccbc72fa
Change-Id: I668be5204547a2606dd314cff73bd0e9ccbc72fa
(cherry picked from commit 70970132)