* Restrict the types for isplit and iconcat to match backends * Admit unimplemented bitwidths to isplit/iconcat * Modify the NarrowInt type instead of shadowing it * Fix filetest failures
* Restrict the types for isplit and iconcat to match backends * Admit unimplemented bitwidths to isplit/iconcat * Modify the NarrowInt type instead of shadowing it * Fix filetest failures