testsuite: Change expectation for bb-slp-over-widen-n.c

testsuite: Change expectation for bb-slp-over-widen-n.c

This patch makes sure we check for
  note: Basic block will be vectorized using SLP
instead of
  optimized: basic block
which will also match
  optimized: basic block part
of which there are many more in an RVV dump.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/bb-slp-over-widen-1.c: Change test expectation.
	* gcc.dg/vect/bb-slp-over-widen-2.c: Ditto.