ubsan: signed integer overflow in display_debug_lines_raw

ubsan: signed integer overflow in display_debug_lines_raw

This one was caused by me unnecessarily promoting an "int adv" to
"int64_t adv".  The expression overflowing was 4259 + 9223372036854775807
with the left number being unsigned int.

	* dwarf.h (DWARF2_Internal_LineInfo): Replace unsigned short
	with uint16_t and unsigned char with uint8_t.  Make li_line_base
	an int8_t.
	* dwarf.c (display_debug_lines_raw): Revert "adv" back to an int.