[IA] Use a single callback for lowerInterleaveIntrinsic [nfc] (#148978) (#149168)

This continues in the direction started by commit 4b81dc7. We
essentially merges the handling for VPStore - currently in
lowerInterleavedVPStore which is shared between shuffle and intrinsic
based interleaves - into the existing dedicated routine.

GitOrigin-RevId: b9adc4a59cb50c98ec0e01645ea5eb64e6628afd
6 files changed