* test/ruby/test_time.rb: add tests to achieve over 70% test coverage of time.c. * test/ruby/test_prec.rb: ditto over 90% for prec.c. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@15399 b2dd03c8-39d4-4d8f-98ff-823fe69b080e