codecvt was deprecated as of C++ 17, and likely should be removed for future compatibility.

In Windows, its included only in pal.windows.cpp, however it doesn't actually seem to be used anywhere.

In Unix, its included only in pal.linux.cpp, and is used to convert a utf8 string to utf16 string, which there for sure is another way to do this.

I noticed this, because this was added in April, and now causes the armel non tizen build to fail, as it does not have access to codecvt.