Clean up JIT diagnostic logging from pre-compile loop

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/lib/sx_vm.ml

@@ -439,7 +439,7 @@ let jit_compile_lambda (l : lambda) globals =
         merged
       end
     in
-    match result with
+    (match result with
     | Dict d when Hashtbl.mem d "bytecode" ->
       let outer_code = code_from_value result in
       let bc = outer_code.vc_bytecode in
@@ -476,7 +476,7 @@ let jit_compile_lambda (l : lambda) globals =
       end
     | _ ->
       Printf.eprintf "[jit] FAIL %s: compiler returned %s\n%!" fn_name (type_of result);
-      None
+      None)
   with e ->
     Printf.eprintf "[jit] FAIL %s: %s\n%!" fn_name (Printexc.to_string e);
     None