selftests/bpf: Remove invariant violation flags

selftests/bpf: Remove invariant violation flags

With the changes to the verifier in previous commits, we're not
expecting any invariant violations anymore. We should therefore always
enable BPF_F_TEST_REG_INVARIANTS to fail on invariant violations. Turns
out that's already the case and we've been explicitly setting this flag
in selftests when it wasn't necessary. This commit removes those flags
from selftests, which should hopefully make clearer that it's always
enabled.

Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/9afce92510a7d44569dc3af63c9b8c608e69298a.1775142354.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>