[ruby/securerandom] Remove no longer used helper methods
Unused since r59801, 782b2050b837206d06767d42d0ea5117921247c8, or https://github.com/ruby/securerandom/commit/52c8e7a85e017f.
https://github.com/ruby/securerandom/commit/38fc2c4427
Added by nobu (Nobuyoshi Nakada) almost 4 years ago
[ruby/securerandom] Remove no longer used helper methods
Unused since r59801, 782b2050b837206d06767d42d0ea5117921247c8,
or https://github.com/ruby/securerandom/commit/52c8e7a85e017f.
https://github.com/ruby/securerandom/commit/38fc2c4427