Remove OBJSTAT and OBJSTATS macros

Remove OBJSTAT and OBJSTATS macros

The OBJSTATS macro seems pretty pointless, so I removed it.  Then when
looking at the OBJSTAT macro as well, I decided to remove it and also
struct objstats.

After this patch, symbols are allocated using a template method that
automatically updates the n_syms member.  This cleans up the code a
little.

Also, nothing ever set objstats::sz_strtab, so this is removed.

Regression tested on x86-64 Fedora 43.

Approved-by: Kevin Buettner <kevinb@redhat.com>