test: Use casts in example programs

Re-enable OP_CAT; yay.

jet_complement_1 is kind of a bitch to use because its input and output
are `u1`. It is from the multi_bit_logic module where every jet works on
`uN` for some bit width `N`. At the same, jet_complement_1 is
effectively the negation jet. jet_negate_1 doesn't exist. I will add
special syntax for boolean operations in a future PR. Until then, we
have to cast incoming bits as well as outgoing bits.

Author: uncomputable

example_progs/cat.simf

@@ -1,12 +1,8 @@
 fn main() {
-    let a: u8 = 0x10;
-    let b: u8 = 0x01;
-    let ab: u16 = (a, b);
+    let ab: u16 = <(u8, u8)>::into((0x10, 0x01));
     let c: u16 = 0x1001;
     jet_verify(jet_eq_16(ab, c));
-    let a: u4 = 0b1011;
-    let b: u4 = 0b1101;
-    let ab: u8 = (a, b);
+    let ab: u8 = <(u4, u4)>::into((0b1011, 0b1101));
     let c: u8 = 0b10111101;
     jet_verify(jet_eq_8(ab, c));
 }

example_progs/function.simf

@@ -1,7 +1,6 @@
 fn checked_add_32(a: u32, b: u32) -> u32 {
     let (carry, sum): (bool, u32) = jet_add_32(a, b);
-    // FIXME: Need to cast `bool` to `u1`
-    // jet_verify(jet_complement_1(carry));
+    jet_verify(<u1>::into(jet_complement_1(<bool>::into(carry))));
     sum
 }
 

src/lib.rs

@@ -66,7 +66,7 @@ mod tests {
             ("add.simf", "empty.wit"),
             ("add.simf", "empty.wit"),
             ("array.simf", "empty.wit"),
-            // ("cat.simf", "empty.wit"),
+            ("cat.simf", "empty.wit"),
             (
                 "checksigfromstackverify.simf",
                 "checksigfromstackverify.wit",