The fuzzers have found the reloc special functions in coff-aarch64.c

All of them need a bfd_reloc_offset_in_range check before accessing
data + reloc_entry->address.  This patch adds the missing checks and
sanity checks reloc offsets in coff_pe_aarch64_relocate_section too.

All of them also need changing to support objdump -W calls to
bfd_simple_get_relocated_section_contents.  At least, secrel_reloc
needs the support, the others might not be present in dwarf debug
sections.

	* coff-aarch64.c (coff_aarch64_rel21_reloc): Range check
	reloc offset.  Support final-linking.
	(coff_aarch64_po12l_reloc): Likewise.
	(coff_aarch64_addr32nb_reloc): Likewise.
	(coff_aarch64_secrel_reloc): Likewise.
	(coff_pe_aarch64_relocate_section): Range check reloc offset.