perf test: Print result for each BPF subtest

perf test: Print result for each BPF subtest

This patch prints each sub-tests results for BPF testcases.

Before:

  # ./perf test BPF
  37: Test BPF filter                                          : Ok

After:

  # ./perf test BPF
  37: Test BPF filter                                          :
  37.1: Test basic BPF filtering                               : Ok
  37.2: Test BPF prologue generation                           : Ok

When a failure happens:

  # cat ~/.perfconfig
  [llvm]
      clang-path = "/bin/false"
  # ./perf test BPF
  37: Test BPF filter                                          :
  37.1: Test basic BPF filtering                               : Skip
  37.2: Test BPF prologue generation                           : Skip

Suggested-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447749170-175898-5-git-send-email-wangnan0@huawei.com
[ Fixed up not to use .func in an anonymous union ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>