speedups for character processing in a multibyte locale when expanding $'...'; cosmet...

speedups for character processing in a multibyte locale when expanding $'...'; cosmetic fix for select command when read returns EOF; fix for a forced interactive shell running under emacs with a pipe for stdin; fix for local nameref variables with the same name as variables in a function's temporary environment; fix for `x=y local -n x' not making `x' visible as a local variable; turn off nameref attribute for local nameref variables converted to arrays