Handle __start_* and __stop_* symbols in --gc-sections

Handle __start_* and __stop_* symbols in --gc-sections

	PR ld/11133
	PR ld/19161
	PR ld/19167
	* elflink.c (_bfd_elf_gc_mark_hook): Delete code handling __start_*
	and __stop_* symbol refs.
	(_bfd_elf_gc_mark_rsec): Add start_stop parameter.  Handle __start_*
	and __stop_* symbol refs here..
	(_bfd_elf_gc_mark_reloc): ..and here.
	* elf-bfd.h (_bfd_elf_gc_mark_hook): Update prototype.
	* elf-eh-frame.c (_bfd_elf_parse_eh_frame): Update
	_bfd_elf_gc_mark_rsec call.