Work around for issue resolving croniter function names, see
https://github.com/ossf/fuzz-introspector/issues/1010 .
Setting the `PYFUZZPACKAGE` environment variable takes coverage from
`2/48` functions reachable to an improved `22/48` reachable. I've also
updated how croniter is imported to have a higher number of matches.
There are still some issues in the callgraph analysis but this is a big
improvement in the metrics.