🐦🛑 Early stopping: Reload weights from best epoch

[mberr]

This PR re-loads the weights from the best epoch when training is stopped.

[migalkin]

Tried on the combination with NodePiece on the ILPC'22 small dataset (20 epochs, patience of 3 epochs) - basically works 🎉 .

Ideally, one needs to add a 'normal' path to the EarlyStopper (didn't try it with the pipeline) like

stopper = EarlyStopper(
    ...,
    best_model_path="/some/path/temp.pth"
)

otherwise it creates a file in the tempdir which results in a hardly every reachable folder like

/var/folders/hb/l6bdhpf92zb3ytwwsj5xblym0000gn/T/best-model-weights-6d0f2c81-6076-4e32-b4fc-90cc48f35718.pt

I am not sure if such temp folder will be automatically cleaned or this file will remain there forever (which is a waste of space).
So maybe out of convenience reasons we could create an early stopper folder in user's PYKEEN_HOME and dump it there for easier cleanup?

[mberr]

Following your suggestion, I

• changed the default checkpoint path to something inside PYKEEN_CHECKPOINTS (cf. 7f976e2)
• added an option to delete the file with the best weights after termination, which is enabled by default (cf. e316b44)

I also

• fixed an error where the inductive mode was not passed to the evaluator
• moved tests around - no big changes here

which blows up the diff a bit 😅

[migalkin]

Good to go!