skip -gfile: call fnmatch without FNM_FILE_NAME

fnmatch is called with the FNM_FILE_NAME flag so that `skip -gfi /usr/*`
doesn't match /usr/include/*.  This makes the file matching feature not
useful for STL headers that reside in multiple directories.  In
addition, the user cannot use a single `*` to match multiple leading
path components.

Let's drop the FNM_FILE_NAME flag and remove the assertion from
gdb_filename_fnmatch (originally for the auto-load feature).
4 files changed