Approximately handle avx512_{packssdw/packsswb/packusdw/packuswb} with
the existing handleVectorPackIntrinsic(), instead of relying on the
default (strict) handler.
Approximately handle avx512_{packssdw/packsswb/packusdw/packuswb} with
the existing handleVectorPackIntrinsic(), instead of relying on the
default (strict) handler.