The destination parameter is still needed as elements of
0 < i < max(vstart, OFFSET) in vd remains unchanged.
The default policy for non-policy (implicit) vslideup intrinsics
will be tail agnostic and mask undisturbed.
This is the 2nd commit of a patch-set that aims to remove the
IsPrototypeDefaultTU special case for the rvv-intrinsics.
Please refer to the cover letter in the 1st commit (D140895) for an overview.