asan: signed integer overflow in display_debug_frames

	* dwarf.c (struct Frame_Chunk): Make col_offset an int64_t.
	Adjust all places allocating col_offset and col_type to use
	the size of the array element rather than the size of a type.
	(frame_display_row): Adjust printing of col_offset.
	(display_debug_frames): Factor out multiplication by
	code_factor and data_factor.  Avoid signed overflow.  Use
	64-bit variables.