perf tools: Test build with libbpf/LIBBPF_DYNAMIC=1

Now that libbpf-devel is more generally available (it is in fedora 34,
for instance), make sure test building with it is performed.

Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>