test: placate Clang's --Wbitwise-instead-of-logical

```
test/test_test.c:58:9: note: cast one or both operands to int to silence this warning
test/test_test.c:58:9: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
    if (!TEST(1, TEST_uint_eq(3u, 3u))
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
test/test_test.c:58:9: note: cast one or both operands to int to silence this warning
```

CLA: Trivial

Reviewed-by: Tomas Mraz <[email protected]>
Reviewed-by: Paul Dale <[email protected]>
(Merged from openssl#18639)