perf tests: Add hybrid cases for 'Roundtrip evsel->name' test

Since for one hw event, two hybrid events are created.

For example,

evsel->idx      evsel__name(evsel)
0               cycles
1               cycles
2               instructions
3               instructions
...

So for comparing the evsel name on hybrid, the evsel->idx
needs to be divided by 2.

  # ./perf test 14
  14: Roundtrip evsel->name                                           : Ok

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210427070139.25256-20-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>