perf parse-events: Extra care around force grouped events

perf parse-events: Extra care around force grouped events

Perf metric (topdown) events on Intel Icelake+ machines require a
group, however, they may be next to events that don't require a group.
Consider:

  cycles,slots,topdown-fe-bound

The cycles event needn't be grouped but slots and topdown-fe-bound need
grouping.

Prior to this change, as slots and topdown-fe-bound need a group forcing
and all events share the same PMU, slots and topdown-fe-bound would be
forced into a group with cycles.

This is a bug on two fronts, cycles wasn't supposed to be grouped and
cycles can't be a group leader with a perf metric event.

This change adds recognition that cycles isn't force grouped and so it
shouldn't be force grouped with slots and topdown-fe-bound.

Fixes: a90cc5a9eeab45ea ("perf evsel: Don't let evsel__group_pmu_name() traverse unsorted group")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.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: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20230719001836.198363-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>