PR27853, Infinite loop in dwarf.c

Not quite infinite but much longer than it need be.  The problem is
triggered by read_and_display_attr_value incrementing "data" past
"end".  read_and_display_attr_value shouldn't do that, but be
defensive.

	PR 27853
	* dwarf.c (display_formatted_table): Test for data >= end rather
	than data == end.
	(process_extended_line_op): Likewise.
	(display_debug_lines_raw): Likewise.
	(display_debug_lines_decoded): Likewise.