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 27a90b1.

"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 <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

Author: cupermir

tools/testing/selftests/bpf/Makefile

@@ -58,6 +58,7 @@ progs/test_pkt_md_access.c-CFLAGS := -fno-strict-aliasing
 progs/test_sk_lookup.c-CFLAGS := -fno-strict-aliasing
 progs/timer_crash.c-CFLAGS := -fno-strict-aliasing
 progs/test_global_func9.c-CFLAGS := -fno-strict-aliasing
+progs/verifier_nocsr.c-CFLAGS := -fno-strict-aliasing
 
 ifneq ($(LLVM),)
 # Silence some warnings when compiled with clang