init.sh: don't let an ephemeral "*.exe" make us skip all dir entries
Not that it's likely to happen, but if I were to remove from a PATH
directory a file named "*.exe" (yes, starting with an asterisk),
at just the right moment, it would have made init.sh ignore all
remaining .exe-suffixed names in that directory.
* tests/init.sh (find_exe_basenames_): Don't give up on a directory if
a file named "*.exe" is removed between the glob expansion and the
processing of that oddly named file.