Revert "Fix flaky serialize_spec.rb, which depends on system time zone:"
Revert "Fix flaky serialize_spec.rb, which depends on system time zone:"

This reverts commit b546f016d786f5d493379fd126d007a63a05bd0b.

rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby