```
and also
- add missing parentheses in fuzz/scriptnum_ops.cpp
- remove useless unsigned int conditional in fuzz/script.cpp
These changes fix 5 compile warnings in gcc 10.
```
Backport of core PR19548.
This is a bit pointless, since for now there is no GCC 10 version for
AFL and the fuzzer sanitizer is not supported. I added another fix to
prevent a `-Werror=missing-braces` warning in `deserialize.cpp`.