selftests/bpf: adapt one more case in test_lru_map to the new target_free

selftests/bpf: adapt one more case in test_lru_map to the new target_free

The below commit that updated BPF_MAP_TYPE_LRU_HASH free target,
also updated tools/testing/selftests/bpf/test_lru_map to match.

But that missed one case that passes with 4 cores, but fails at
higher cpu counts.

Update test_lru_sanity3 to also adjust its expectation of target_free.

This time tested with 1, 4, 16, 64 and 384 cpu count.

Fixes: d4adf1c9ee77 ("bpf: Adjust free target to avoid global starvation of LRU map")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20250625210412.2732970-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>