[Bug target/84371] test case gcc.target/powerpc/builtins-3.c fails on power9

[willschm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84371

--- Comment #4 from Will Schmidt <willschm at gcc dot gnu.org> ---
The scope of the problem here seems to have changed in the last week.  
Now seeing a number of 
 " error: builtin function '__builtin_altivec_neg_v2df' requires the
'-mpower8-vector' option "
will investigate, & probably run the builtin-3 tests through a blender to sort
this out..