[testsuite] Fix PR93935 to guard case under vect_hw_misalign

This patch is to apply the same fix as r267528 to another similar case
bb-slp-over-widen-2.c which requires misaligned vector access.

gcc/testsuite/ChangeLog

    PR testsuite/93935
    * gcc.dg/vect/bb-slp-over-widen-2.c: Expect basic block vectorized
    messages only on vect_hw_misalign targets.

gcc/testsuite/ChangeLog

+2020-03-13  Kewen Lin  <linkw@gcc.gnu.org>
+
+	PR testsuite/93935
+	* gcc.dg/vect/bb-slp-over-widen-2.c: Expect basic block vectorized
+	messages only on vect_hw_misalign targets.
+
 2020-03-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/89229

gcc/testsuite/gcc.dg/vect/bb-slp-over-widen-2.c

@@ -63,4 +63,4 @@ main (void)
 /* { dg-final { scan-tree-dump "demoting int to signed short" "slp2" { target { ! vect_widen_shift } } } } */
 /* { dg-final { scan-tree-dump "demoting int to unsigned short" "slp2" { target { ! vect_widen_shift } } } } */
 /* { dg-final { scan-tree-dump {\.AVG_FLOOR} "slp2" { target vect_avg_qi } } } */
-/* { dg-final { scan-tree-dump-times "basic block vectorized" 2 "slp2" } } */
+/* { dg-final { scan-tree-dump-times "basic block vectorized" 2 "slp2" { target vect_hw_misalign } } } */