perf test: Check test suite description properly

Currently perf test checks the given string with descriptions for both
test suites and cases (subtests).  But sometimes it's confusing since
the subtests don't contain the important keyword.

I think it's better to check the suite level and run the whole suite
together if it matches description in the suite.

Before:
  $ perf test hwmon
  (no output)

After:
  $ perf test hwmon
   10: Hwmon PMU                                                       :
   10.1: Basic parsing test                                            : Ok
   10.2: Parsing without PMU name                                      : Ok
   10.3: Parsing with PMU name                                         : Ok

And keep the existing behavior when it only matches test description only.

  $ perf test "Equal cpu map"
   39.5: Equal cpu map                                                 : Ok

Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250701201027.1171561-1-namhyung@kernel.org


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