perf test: Send list output to stdout rather than stderr

Follow the workload listing in using stdout rather than
stderr. Correct the numbering of sub-tests to be 1.1 rather than 1:1.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250110045736.598281-3-irogers@google.com


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