Adds a couple of perf_event_attr tests for the fix introduced in [1].
The tests check that the correct sample_period value is set in the
struct perf_event_attr of the arm_spe events.

[1]: https://lore.kernel.org/all/20220118144054.2541-1-german.gomez@arm.com/Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: German Gomez <german.gomez@arm.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220126160710.32983-1-german.gomez@arm.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>