misc(treemap): fix colors

[connorjclark]

1. Changed the stableHasher function to recycle items, so that colors never run out.
2. I had added a fake jquery duplication to debug.json, but it turns out that there were visible duplicates but they were given white because of 1). So I removed the fake duplication.
3. Refactored ViewMode.highlight. I figured this property should be responsible for declaring what color a specific node should be.

ref #11254