Difference in performance between `conda-forge` and defaults?

[jaimergp]

While running tests for #317 (Linux only), I've noticed on the conda-forge Docker image each attempt takes an average of 15-16s, while on the defaults one it consistently goes down to 5s. I don't know if it's the libsolv version (0.7.26 vs 0.7.24, respectively), or some optimization flags that conda-forge does not set but defaults does.

Leaving this here to investigate in the future, in case it's an obvious win at little cost :)

Ideas to try:

• [ ] Fetch the duration data from each test run and compare the matched conda-forge&defaults pairs.

[jonashaag]

We should send fewer packages to libsolv by "presolving", see https://github.com/mamba-org/mamba/issues/2824