This reverts commit ec8808c302 but
retains its test, as the problem it fixed is now solved by having the
TZ backend validate the ID it's passed, so that it now only accepts
valid POSIX zone-descriptions and valid IANA IDs. The former were
being excluded by this check.
Amended a POSIX test to fail with the check in place; it passes now.
Change-Id: I0d5e8c6e0a315ac2509f3d23bebb52aede8f79d0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Robert Löhning <robert.loehning@qt.io>