tree-optimization/107254 - check and support live lanes from permutes

tree-optimization/107254 - check and support live lanes from permutes

The following fixes an omission from adding SLP permute nodes which
is live lanes originating from those.  We have to check that we
can extract the lane and have to actually code generate them.

	PR tree-optimization/107254
	* tree-vect-slp.cc (vect_slp_analyze_node_operations_1):
	For permutes also analyze live lanes.
	(vect_schedule_slp_node): For permutes also code generate
	live lane extracts.

	* gfortran.dg/vect/pr107254.f90: New testcase.