More fixes for invalid memory accesses triggered by fuzzed binaries.

More fixes for invalid memory accesses triggered by fuzzed binaries.

	PR binutils/17531
	* dwarf.c (alloc_num_debug_info_entries): New variable.
	(process_debug_info): Set it.  Use it to avoid displaying
	attributes for which there is no info.
	(display_debug_abbrev): Check that the debug_info_entry index is
	valid before using it.
	(display_loc_list_dwo): Likewise.
	(process_cu_tu_index): Add range check for an overlarge dw_sect
	value.
	(free_debug_memory): Reset alloc_num_debug_info_entries.
	* readelf.c (slurp_ia64_unwind_table): Warn if the reloc could not
	be indentified.
	(dynamic_section_mips_val): Warn if the timestamp is invalid.
	(print_mips_got_entry): Add a data_end parameter.  Warn if a read
	would go beyond the end of the data, and return an error value.
	(process_mips_specific): Do not read options from beyond the end
	of the section.
	Correct code to display optional data at the end of an option.
	Warn if there are too many GOT symbols.
	Update calls to print_mips_got_entry, and handle error returns.