Hash lookup is silly when we can attach the line table info directly
to sections instead. Worse, hash lookup fails when we have multiple
sections with the same name.
gas/
* dwarf2dbg.c (all_segs_hash): Delete.
(get_line_subseg): Delete last_seg, last_subseg, last_line_subseg.
Retrieve line_seg for section via seg_info.
* subsegs.h (segment_info_typet): Add dwarf2_line_seg.
gas/testsuite/
* gas/elf/group2.d, * gas/elf/group2.s: New test.
* gas/elf/elf.exp: Run it.