selftests/bpf: Add uprobe_multi api test

Adding uprobe_multi test for bpf_program__attach_uprobe_multi
attach function.

Testing attachment using glob patterns and via bpf_uprobe_multi_opts
paths/syms fields.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-21-jolsa@kernel.org


Signed-off-by: Alexei Starovoitov <ast@kernel.org>