In commit ec8719ccbf, I added switch statements with all expected
shift counts to vector8_shift_{left,right} because vshlq_n_u32()
and vshrq_n_u32() require integer literals. But we can use
vshlq_u32() instead for both cases, which does not require an
integer literal, thereby avoiding the need for the switch
statements. This compiles to the same machine code on newer
versions of popular compilers.
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Discussion: https://postgr.es/m/akWxkA-mszMm57cV%40nathan
763ee7ea00