cranelift: Remove booleans (#5031)

Remove the boolean types from cranelift, and the associated instructions breduce, bextend, bconst, and bint. Standardize on using 1/0 for the return value from instructions that produce scalar boolean results, and -1/0 for boolean vector elements.

Fixes #3205

Co-authored-by: Afonso Bordado <afonso360@users.noreply.github.com>
Co-authored-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Co-authored-by: Chris Fallin <chris@cfallin.org>

cranelift/codegen/src/isa/riscv64/inst/args.rs

@@ -1189,10 +1189,8 @@ impl LoadOP {
             return if t == F32 { Self::Flw } else { Self::Fld };
         }
         match t {
-            B1 | B8 => Self::Lbu,
-            B16 => Self::Lhu,
-            B32 | R32 => Self::Lwu,
-            B64 | R64 | I64 => Self::Ld,
+            R32 => Self::Lwu,
+            R64 | I64 => Self::Ld,
 
             I8 => Self::Lb,
             I16 => Self::Lh,