CBE: implement popCount, byteSwap, bitReverse for ints <= 128 bits

This folds the airCountZeroes() code from
226fcd7c709ec664c5d883042cf7beb3026f66cb back into airBuiltinCall(),
since most of these builtins happen to require the same arguments and
can be unified under a common function signature.
d0277a3d17Daniele Cocca committed on 3/13/2022, 9:59:15 AMparent87744a7
6 files changedLine totals unavailable