Prevent division by 0

[qsr]

When checking whether the operand is not 0, one should only look on 32 bits when doing a 32 bits operation.

[Alan-Jowett]

@qsr Would you object to adding this test to https://github.com/Alan-Jowett/bpf_conformance/tree/main/tests?

This seems like a useful test that might affect other BPF runtimes and if added to the conformance suite we check for this issue in other implementations.

[qsr]

@qsr Would you object to adding this test to https://github.com/Alan-Jowett/bpf_conformance/tree/main/tests?

This seems like a useful test that might affect other BPF runtimes and if added to the conformance suite we check for this issue in other implementations.

No problem: Alan-Jowett/bpf_conformance#198

[coveralls]

coverage: 83.35%. remained the same
when pulling 016bed6 on qsr:fix_div32
into 215b8a3 on iovisor:main.