Module existance check done too often

[Flamefire]

Similar to the pip check being run repeatably where a single check would suffice I see the module existance check done multiple times.

For SciPy-bundle-2022.05 every module seems to get checked up to 32 times (zlib), some (foss) 17 times.

This looks excessive although it seems to be able to use a cache making it fast. But it clutters the log a lot.