test__checkevent_complex_name will use an "event" format which if not
present, such as with a placeholder PMU, will cause test failures. Skip
the test in this case to avoid failures in restricted environments.

Add perf_pmu__has_format utility as a general PMU utility.

Fixes: 628eaa4e ("perf pmus: Add placeholder core PMU")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230706183705.601412-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>