Revert "Refactor Scan_Convert_P20_Into_Space()"

This reverts commit 553ba87d0311e4e4c64f2321b5aa654df0c4ae29.

The above commit added a call to strcpy(), with arguments that
overlapped. The behaviour of such a call is undefined, and can lead to
test failures.

https://bugzilla.gnome.org/show_bug.cgi?id=728743