selftests/bpf: Disable strict aliasing for verifier_nocsr.c

selftests/bpf: Disable strict aliasing for verifier_nocsr.c

verfifier_nocsr.c fails to compile in GCC. The reason behind it was
initially explained in commit 27a90b14b93d3b2e1efd10764e456af7e2a42991.

"A few BPF selftests perform type punning and they may break strict
aliasing rules, which are exploited by both GCC and clang by default
while optimizing.  This can lead to broken compiled programs."

Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240819151129.1366484-2-cupertino.miranda@oracle.com