perf test: Simplify data symbol test

Now the workload will end after 1 second.  Just run it with perf instead
of waiting for the background process.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Thomas Falcon <thomas.falcon@intel.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Leo Yan <leo.yan@arm.com>
Link: https://lore.kernel.org/r/20250304022837.1877845-7-namhyung@kernel.org


Signed-off-by: Namhyung Kim <namhyung@kernel.org>