perf tests: Add daemon reconfig test

Add a test for daemon reconfiguration. The test changes the
configuration file and checks that the session is changed properly.

Committer testing:

  [root@five ~]# perf test daemon
  76: daemon operations                                               : Ok
  [root@five ~]# time perf test daemon
  76: daemon operations                                               : Ok

  real	0m6.055s
  user	0m0.174s
  sys	0m0.147s
  [root@five ~]# time perf test -v daemon
  76: daemon operations                                               :
  --- start ---
  test child forked, pid 786863
  test daemon list
  test daemon reconfig
  test child finished with 0
  ---- end ----
  daemon operations: Ok

  real	0m6.127s
  user	0m0.222s
  sys	0m0.165s
  [root@five ~]#

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20210208200908.1019149-21-jolsa@kernel.org


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