[BugFix] Fixing CVRPTW bugs during multistart solution generation

[ahottung]

Description

This pull request fixes some very minor bugs that occur when using the CVRPTW env during multistart solution generation. Additionally, it adds the CVRPTW to the problems considered in the policy test cases.

Types of changes

What types of changes does your code introduce? Remove all that do not apply:

• [ x] Bug fix (non-breaking change which fixes an issue)

Checklist

Go over all the following points, and put an x in all the boxes that apply. If you are unsure about any of these, don't hesitate to ask. We are here to help!

• [ ] My change requires a change to the documentation.
• [ x] I have updated the tests accordingly (required for a bug fix or a new feature).
• [ ] I have updated the documentation accordingly.

[fedebotu]

LGTM, @cbhua @ngastzepeda you can merge after your approval

[fedebotu]

LGTM, merging now!