Revert "Must pass encoding into getCodingErrorActions after 7c53e5bc"

This reverts commit 0b6f1aa9510057a1b89292c5e43ebb4c76b935f6.
Use old replacement behavior for RubyIO for now.

I'm not sure what encoding to use to guarantee we have an "out"
encoding to use to select the default replacement character, so
I'm just having RubyIO do the old logic for now. @enebo may be
able to help here.