### Description

This PR renames the `ReverseTopological` graph store implementation to
`AdjacencyMap`. The reasoning here is that we can implement any graph
traversal algorithm on top of `AdjacencyMap`, not just reverse
topological.

This PR also adds a `reverse_topological_from_node` iterator method to
only traverse the subgraph from a given node.

Next.js PR:
https://github.com/vercel/next.js/compare/alexkirsz/web-866-adjacency-map?expand=1

### Testing Instructions

N/A