Fix type-checking of select to handle non-concrete condition type

Testing SROA I discovered that the current type-checking procedure for ternary nodes fails to type-check select if the condition's type is not concrete yet. For example, on main the new example products.hir fails to compile with

cargo run --bin hercules_driver -- hercules_samples/products.hir "SROA Xdot(true)"

(though if the passes are only Xdot(true) type-checking succeeds).

hercules_ir/src/typecheck.rs

@@ -688,26 +688,19 @@ fn typeflow(
                 return Error(String::from("Ternary node must have exactly three inputs."));
             }
 
-            if let Concrete(id) = inputs[0] {
-                match op {
-                    TernaryOperator::Select => {
+            match op {
+                TernaryOperator::Select => {
+                    if let Concrete(id) = inputs[0] {
                         if !types[id.idx()].is_bool() {
                             return Error(String::from(
                                 "Select ternary node input cannot have non-bool condition input.",
                             ));
                         }
-
-                        let data_ty = TypeSemilattice::meet(inputs[1], inputs[2]);
-                        if let Concrete(data_id) = data_ty {
-                            return Concrete(data_id);
-                        } else {
-                            return data_ty;
-                        }
                     }
+
+                    TypeSemilattice::meet(inputs[1], inputs[2])
                 }
             }
-
-            Error(String::from("Unhandled ternary types."))
         }
         Node::Call {
             control: _,