selftests/bpf: Fix ARG_PTR_TO_LONG {half-,}uninitialized test

The assumption of 'in privileged mode reads from uninitialized stack locations
are permitted' is not quite correct since the verifier was probing for read
access rather than write access. Both tests need to be annotated as __success
for privileged and unprivileged.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240913191754.13290-6-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Author: borkmann

tools/testing/selftests/bpf/progs/verifier_int_ptr.c

@@ -8,7 +8,6 @@
 SEC("socket")
 __description("ARG_PTR_TO_LONG uninitialized")
 __success
-__failure_unpriv __msg_unpriv("invalid indirect read from stack R4 off -16+0 size 8")
 __naked void arg_ptr_to_long_uninitialized(void)
 {
 	asm volatile ("					\
@@ -36,9 +35,7 @@ __naked void arg_ptr_to_long_uninitialized(void)
 
 SEC("socket")
 __description("ARG_PTR_TO_LONG half-uninitialized")
-/* in privileged mode reads from uninitialized stack locations are permitted */
-__success __failure_unpriv
-__msg_unpriv("invalid indirect read from stack R4 off -16+4 size 8")
+__success
 __retval(0)
 __naked void ptr_to_long_half_uninitialized(void)
 {