Turbopack: Compact only at the end for short sessions (#82224)
### What?
Change the compaction behavior for "short sessions" (like next build). A longer "short session" might commit to the DB multiple times (every 60s currently), which previously resulted in compactions happening after multiple commits to the database. As compactions are expensive and memory hungry, we want to avoid them until the end of the session. At the end of the session we can run it in parallel to node.js SSG.
