Also:
* split benchmark functions to make sure no one compares across parsers.
* testdata file have meaningful names reflecting the type representation
* promtestdata.txt now has all types, taken directly from long running Prometheus (https://demo.do.prometheus.io/)
Needed for https://github.com/prometheus/prometheus/pull/15731
Signed-off-by: bwplotka <bwplotka@gmail.com>
