* test/-ext-/time/test_new.rb (test_timespec_new): Time#gmtoff values
are the same only when both or neither of the Time objects are in
summer time (daylight-saving time).
* test/-ext-/time/test_new.rb (test_timespec_new): change a gmtoff
test to a better one that does not depend on whether the current
time is in summer time or not.
merge revision(s) 54137,54184: [Backport #12227]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@54418 b2dd03c8-39d4-4d8f-98ff-823fe69b080e