Revert "selftests/bpf: check null propagation only neither reg is PTR_TO_BTF_ID"

stable inclusion
from stable-v5.10.166
commit a7345145e7bdd7cfc4359e16a23ebde846c8ebf9
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I87FRA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a7345145e7bdd7cfc4359e16a23ebde846c8ebf9



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This reverts commit 3093027183f2846365a76b2fb1e1309f1960084a.

Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>