Stabilize automated performance tests

[pirelenito]

There is currently a very high variation on the performance numbers we are getting when running via GitHub actions.

This PR does three main changes:

• Increases the time we take to collect samples for the markerFacet example.
• Changes the target performance number for listMemoFacet to 70.
• Make the script only fail when we go above the target (it would fail when going below as well).

We are still learning what are the best practices on automating this checks, and for the meantime we should still not have them as merge blockers (given they are not yet quite stable).