TST: avoid side effects across tests
TST: avoid side effects across tests

Discovered a possible side effect across tests, while experimenting.
Fixing it here, to be future-proof, although in the current state of the
codebase it is not a problem

aabadie/joblib,aabadie/joblib,tomMoral/joblib,lesteve/joblib,joblib/joblib,joblib/joblib,karandesai-96/joblib,tomMoral/joblib,lesteve/joblib,karandesai-96/joblib