[Bug testsuite/89834] New test case gcc.dg/vect/pr81740-2.c introduced in r269938 fails on power 7

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89834

--- Comment #2 from seurer at gcc dot gnu.org ---
I added

/* { dg-require-effective-target vect_hw_misalign } */

to the test and it comes out now as not supported on power 7 and thus does not
fail.  Note that I only tried this there.