selftests/bpf: Fix outdated test on storage->smap

selftests/bpf: Fix outdated test on storage->smap

bpf_local_storage_free() already does not rely on local_storage->smap
since switching to kmalloc_nolock(). As local_storage->smap is removed,
fix the outdated test by dropping the local_storage->smap check. Keep
the second map in task local storage map test to test that multiple
elements can be added to the storage similar to sk storage test.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20260205222916.1788211-18-ameryhung@gmail.com