[ruby/date] Removed workaround for assert_ractor

ruby/date@700e44ef54

Author: hsbt

test/date/test_date_ractor.rb

@@ -5,10 +5,6 @@
 class TestDateParseRactor < Test::Unit::TestCase
   def code(klass = Date, share: false)
     <<~RUBY.gsub('Date', klass.name)
-      class Ractor
-        alias value take
-      end unless Ractor.method_defined? :value # compat with Ruby 3.4 and olders
-
       share = #{share}
       d = Date.parse('Aug 23:55')
       Ractor.make_shareable(d) if share