Negative sequence lengths during testing on DWM

[tsjayram]

Describe the bug
When I run mip-tester on the DWM model, the seq_length parameter is reported as negative.

To Reproduce
Steps to reproduce the behavior:
E.g., run mip-tester --model experiments/SerialRecallCommandLines/DWM/20190329_123610/models/model_best.pt --config configs/dwm_baselines/dwm/serial_recall.yaml
on any trained model

Desktop (please complete the following information):

• OS: both MacOS and Ubuntu
• Python version 3.7
• PyTorch version 1.0

Additional context
The problem seems to occur when min_seq_length and max_seq_length are both above 127

[tsjayram]

I noticed that the negative values in test_dict after executing the line

mi-prometheus/miprometheus/workers/tester.py

Line 316 in 44098d2

for test_dict in self.dataloader: