Fix ZoneInfoDBTest.testGoodOverride

When executed under the CTS environment some of the tests in
ZoneInfoDBTest assumed:
1) The device was booted with all tzinfo files present and that
they don't change (i.e. so the runtime's static TimeZone
singleton reflects the contents of the file system at the
time the test is executed).
2) The number of timezone IDs in /data/misc/zoneinfo/tzdata,
/system/usr/share/zoneinfo/tzdata are the same (if
assumption 1 holds).

This change modifies the tests to only use the (unchanging)
/system/usr/share/zoneinfo/tzdata file and avoid use of the
TimeZone class.

Bug: 15382201
Change-Id: I8d3b1ea52a2147e7afaa302803c834539bd01db9
1 file changed