Revert "Fix pp to correctly handle hashes"

* This reverts commit ce8c0b1.
* Ruby 3 kwargs are implemented now, and this is needed to pass
  PPTestModule::PPSingleLineTest#test_hash_in_array and also
  pp [Hash.ruby2_keywords_hash({})]

Author: eregon

lib/mri/pp.rb

@@ -237,11 +237,7 @@ def seplist(list, sep=nil, iter_method=:each) # :yield: element
         else
           sep.call
         end
-        if defined?(::TruffleRuby)
-          yield(*v)
-        else
-          yield(*v, **{})
-        end
+        yield(*v, **{})
       }
     end