Test SEC_HAS_CONTENTS before reading section contents

Test SEC_HAS_CONTENTS before reading section contents

bfd_malloc_and_get_section does size sanity checking before allocating
memory and reading contents.  These size checks are not done for bss
style sections, because they typically don't occupy file space and
thus can't be compared against file size.  However, if you are
expecting to look at something other than a whole lot of zeros, don't
allow fuzzers to avoid the size checking.

	* cofflink.c (process_embedded_commands): Don't look at
	sections without SEC_HAS_CONTENTS set.
	* cpu-arm.c (bfd_arm_update_notes): Likewise.
	(bfd_arm_get_mach_from_notes): Likewise.
	* elf-eh-frame.c (_bfd_elf_parse_eh_frame): Likewise.
	* elf-hppa.h (elf_hppa_sort_unwind): Likewise.
	* elf-m10300.c (mn10300_elf_relax_section): Likewise.
	* elf-sframe.c (_bfd_elf_parse_sframe): Likewise.
	* elf.c (_bfd_elf_print_private_bfd_data): Likewise.
	* elf32-arm.c (bfd_elf32_arm_process_before_allocation): Likewise.
	* elf32-avr.c (avr_elf32_load_property_records): Likewise.
	* elf32-ppc.c (_bfd_elf_ppc_set_arch): Likewise.
	(ppc_elf_get_synthetic_symtab, ppc_elf_relax_section): Likewise.
	* elf64-ppc.c (ppc64_elf_get_synthetic_symtab): Likewise.
	(opd_entry_value, ppc64_elf_edit_opd, ppc64_elf_edit_toc): Likewise.
	* elf64-x86-64.c (elf_x86_64_get_synthetic_symtab): Likewise.
	* elflink.c (elf_link_add_object_symbols): Likewise.
	(bfd_elf_get_bfd_needed_list): Likewise.
	* elfnn-aarch64.c (get_plt_type): Likewise.
	* elfxx-mips.c (_bfd_mips_elf_get_synthetic_symtab): Likewise.
	* linker.c (_bfd_handle_already_linked): Likewise.
	* opncls.c (bfd_get_debug_link_info_1): Likewise.
	(bfd_get_alt_debug_link_info, get_build_id): Likewise.
	* peXXigen.c (pe_print_idata, pe_print_pdata): Likewise.
	(_bfd_XX_print_ce_compressed_pdata, pe_print_reloc): Likewise.
	* pei-x86_64.c (pex64_bfd_print_pdata_section): Likewise.
	* stabs.c (_bfd_link_section_stabs): Likewise.
	(_bfd_discard_section_stabs): Likewise.
	* xcofflink.c (_bfd_xcoff_get_dynamic_symtab_upper_bound): Likewise.
	(_bfd_xcoff_canonicalize_dynamic_symtab): Likewise.
	(_bfd_xcoff_get_dynamic_reloc_upper_bound): Likewise.
	(_bfd_xcoff_canonicalize_dynamic_reloc): Likewise.
	(xcoff_link_add_dynamic_symbols): Likewise.
	(xcoff_link_check_dynamic_ar_symbols): Likewise.
	(bfd_xcoff_build_dynamic_sections): Likewise.