tree-optimization/110221 - SLP and loop mask/len

tree-optimization/110221 - SLP and loop mask/len

The following fixes the issue that when SLP stmts are internal defs
but appear invariant because they end up only using invariant defs
then they get scheduled outside of the loop.  This nice optimization
breaks down when loop masks or lens are applied since those are not
explicitly tracked as dependences.  The following makes sure to never
schedule internal defs outside of the vectorized loop when the
loop uses masks/lens.

	PR tree-optimization/110221
	* tree-vect-slp.cc (vect_schedule_slp_node): When loop
	masking / len is applied make sure to not schedule
	intenal defs outside of the loop.

	* gfortran.dg/pr110221.f: New testcase.