Allow case expressions with a single alternative to be floated in.
This change generalizes support for floating in case expressions. Previously, case expression with an unlifted scrutinee and a single DEFAULT alternative were floated in. In particular, this allowed array index operations to be floated in. We also want to float in SIMD unpack primops, which return an unboxed tuple of scalars, thus the generalization.
Showing with 12 additions and 4 deletions