Running shellcheck on record_sideband.sh throws below
warning:

	In tests/shell/record_sideband.sh line 25:
	  if ! perf record -o ${perfdata} -BN --no-bpf-event -C $1 true 2>&1 >/dev/null
	    ^--^ SC2069: To redirect stdout+stderr, 2>&1 must be last (or use '{ cmd > file; } 2>&1' to clarify).

This shows shellcheck warning SC2069 where the redirection
order needs to be fixed. Use "cmd > /dev/null 2>&1" to fix
the redirection of perf record output

Fixes: 23b97c7ee963 ("perf test: Add test case for record sideband events")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: disgoel@linux.vnet.ibm.com
Link: https://lore.kernel.org/r/20231013073021.99794-3-atrajeev@linux.vnet.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Add a new test case to record sideband events for all CPUs when tracing
selected CPUs

Test result:

  # ./perf test list 2>&1 | grep 'perf record sideband tests'
   95: perf record sideband tests
  # ./perf test 95
   95: perf record sideband tests                                      : Ok

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20230904023340.12707-6-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>