Make MaskForRegisterInSequence return tuple with results.

That function is, presumably, helper for vector intrinsic processing,
not actual intrinsic, but since it's called from interpreter, not from
other intrinsics it's better to turn it into a proper intrinsic.

Test: m berberis_all

Change-Id: Ie6f94383f7b90d69bc1d0a9d42ec95301c6f44ef
3 files changed