lto.cc: OpenMP's offload_handle_link_vars - fix for global variables (2/2) [PR127273]

Commit r12-7776-g1002a7ace111d7
  LTO: Fixes for renaming issues with offload/OpenMP [PR104285]
moved the call to offload_handle_link_vars after the renaming of
same-named static variables happened.

However, it missed to remove the original call - such that the
function is always called twice, walking the same node twice.

In offload_handle_link_vars, the call to varpool_node::finalize_decl should
be be after FOR_EACH_VARIABLE avoid modifying the varpool while walking it.
(Albeit new items get appended to the front such that '->next' walks
are not affected by added items in the current implementation.)

[See r17-4073-ga6310d58aac505 for (1/2).]

gcc/lto/ChangeLog:

	PR middle-end/127273
	* lto.cc (offload_handle_link_vars): Remove has-value-expr check;
	store link vars and processing them after walking the varpool.
	(lto_main): Remove duplicated offload_handle_link_vars call.