Only test non-DST timezone

SunOS doesn't set DST timezone for UTC, so only non-DST should be tested.

issue4380
review12771002
(grafted from 0fde10af95a33758ce4a01ecf82d6cb2e2cf9918)

--HG--
branch : 3.4
extra : source : 0fde10af95a33758ce4a01ecf82d6cb2e2cf9918