bpf: Allow calling bpf_prog_test kfuncs in tracing programs

In addition to TC hook, enable these in tracing programs so that they
can be used in selftests.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220809213033.24147-2-memxor@gmail.com


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