PR22443, Global buffer overflow in _bfd_elf_get_symbol_version_string

PR22443, Global buffer overflow in _bfd_elf_get_symbol_version_string

Symbols like *ABS* defined in bfd/section.c:global_syms are not
elf_symbol_type.  They can appear on relocs and perhaps other places
in an ELF bfd, so a number of places in nm.c and objdump.c are wrong
to cast an asymbol based on the bfd being ELF.  I think we lose
nothing by excluding all section symbols, not just the global_syms.

	PR 22443
	* nm.c (sort_symbols_by_size): Don't attempt to access
	section symbol internal_elf_sym.
	(print_symbol): Likewise.  Don't call bfd_get_symbol_version_string
	for section symbols.
	* objdump.c (compare_symbols): Don't attempt to access
	section symbol internal_elf_sym.
	(objdump_print_symname): Don't call bfd_get_symbol_version_string
	for section symbols.