clean up unused arrays

[tapastro]

Partially addresses JP-3697

This PR addresses high memory usage in jump step by deleting some large arrays after use, and moving initialization of other arrays to the time at which they are needed.

Checklist

• [ ] added entry in CHANGES.rst (either in Bug Fixes or Changes to API)
• [ ] updated relevant tests
• [ ] updated relevant documentation
• [ ] updated relevant milestone(s)
• [ ] added relevant label(s)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 82.84%. Comparing base (2112773) to head (e7400b6). Report is 69 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #277 +/- ## ========================================== - Coverage 84.32% 82.84% -1.49% ========================================== Files 41 41 Lines 7529 7531 +2 ========================================== - Hits 6349 6239 -110 - Misses 1180 1292 +112 ```

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[tapastro]

Closing this - it appears that this breaks code in unexpected ways, and I don't have the time to tackle the full refactor.