[PAC][lld] Test warning emitted for non-PAuth-marked files with `-z pac-plt` (#112958)
b6162622c054f changed semantics of `-z pac-plt` initially introduced in
e208208a3132c, so, the following comment from test/ELF/aarch64-feature-pac.s
is no longer true:
> There are no warnings in this case as the choice to use PAC in PLT entries
> is orthogonal to the choice of using PAC in relocatable objects. The
> presence of the PAC .note.gnu.property is an indication of preference by
> the relocatable object.
This patch updates the test so we ensure a warning is emitted for an
input file when `-z pac-plt` is passed but the file does not have
GNU_PROPERTY_AARCH64_FEATURE_1_PAC set in GNU_PROPERTY_AARCH64_FEATURE_1_AND
property.