selftests/bpf: Remove tests for zeroed-array kptr

selftests/bpf: Remove tests for zeroed-array kptr

bpf_mem_alloc() doesn't support zero-sized allocation, so removing these
tests from test_bpf_ma test. After the removal, there will no definition
for bin_data_8, so remove 8 from data_sizes array and adjust the index
of data_btf_ids array in all test cases accordingly.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231216131052.27621-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>