perf test arm-spe: Check if perf-record hangs when recording workload with forks

Add shell test to check if perf-record hangs when recording an arm_spe
event with forks.

The test FAILS if the Kernel is not patched with Commit 961c3912

 ("perf:
Always wake the parent event").

Unpatched Kernel:

  $ perf test -v 90
  90: Check Arm SPE doesn't hang when there are forks
  --- start ---
  test child forked, pid 14232
  Recording workload with fork
  Log lines = 90 /tmp/__perf_test.stderr.0Nu0U
  Log lines after 1 second = 90 /tmp/__perf_test.stderr.0Nu0U
  SPE hang test: FAIL
  test child finished with -1
  ---- end ----
  Check Arm SPE trace data in workload with forks: FAILED!

Patched Kernel:

  $ perf test -v 90
  90: Check Arm SPE doesn't hang when there are forks
  --- start ---
  test child forked, pid 2930
  Compiling test program...
  Recording workload...
  Log lines = 478 /tmp/__perf_test.log.026AI
  Log lines after 1 second = 557 /tmp/__perf_test.log.026AI
  SPE hang test: PASS
  Cleaning up files...
  test child finished with 0
  ---- end ----
  Check Arm SPE trace data in workload with forks: Ok

Reviewed-by: James Clark <james.clark@arm.com>
Reviewed-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: German Gomez <german.gomez@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220228165655.3920-1-german.gomez@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>