LTO object insertion point

LTO object insertion point

This is a mostly cosmetic fix for cases like PR24873 where LTO
recompiled objects were supposed to be inserted inside a group.  The
specific case handled by this patch is when the first file inside a
group is an archive, the first file claimed by the plugin.  Prior to
this patch we would have inserted the recompiled objects before the
group, which doesn't matter really since the entire group will be
reloaded, but it looks a little wrong in map files.

	PR 24873
	* ldlang.c (find_replacements_insert_point): Return "before" flag.
	(find_next_input_statement): New function.
	(lang_process): When placing recompiled LTO objects before a
	claimed archive, place them immediately before in the statement
	list.