perf build tests: Do parallell builds with 'build-test'

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-jhmnf9g7y9ryqcjql00unk5y@git.kernel.org


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