This finally solves issues with DBSC console codepages, and in
general improves the console codepage switching. When
module_initialized, all the possible encoding INI settings with
regard to possible modifications are set, and that's the
right moment to switch the console codepage in regard to I/O.
CJK glyphs might take more than 1 cell, so then  visual issues
can occur, when switching console codepage back and forth. Users
are free to use ini_set(), but any visual issues are then up to
the user responsibility.

If PHP CLI is used with programs with no Unicode support, the default
PHP console codepage might cause backward incompatible behaviors. This
is solved with this patch by separating the handling of I/O codepage.
As per https://wiki.php.net/rfc/default_encoding input_encodnig and
output_encoding are centralized INI settings, so they're used for the
purpose of adjusting the codepage. This gives user the ability to use
UTF-8 internally, while letting the system API to convert the output
to a compatible codepage. This also might solve the font issues on
systems without good true type support.

Note, that there no change to the default behavior - if input and
output encoding are not set, which is the default case, the default
charset applies to both console input and output. The patch is just
a compilment to the backward compatibility, not more and not less.