code
(https://github.com/ruby/reline/pull/800)

* Remove invalid encoding string "\M-[char]" from test code, remove unused code/arg/options

* Omit unicode unnoralized input test in non-utf8 testcase

* Remove helper method and constant no longer used in testcode

* Change key binding test to use realistic bytes instead of invalid byte sequence

* Remove invalid byte sequence input from rendering test

yamatanooroti handles invalid byte sequence input "\M-[char]" and converts it to "\e[char]"
We don't need to use these invalid byte sequence and rely on the hack implemented in yamatanooroti

https://github.com/ruby/reline/commit/f09e7b154c