Re-apply r63848 (Optimize Time.utc)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63857 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Re-apply r63848 (Optimize Time.utc)
have leap seconds on the first call of init_leap_second_info()
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63857 b2dd03c8-39d4-4d8f-98ff-823fe69b080e