Turbopack: compute async info from module graph (#76118)
Just quickly propagate this boolean in the graph, as opposed to chunking. Enables us to eventually get rid of `AvailableModules` and also to reimplement chunking generally.
Closes PACK-3667
TODO:
- [x] Per-layout segment computation of the async info
- [x] Fix computation of the async info to handle cycles
```
testing against 0293c96cf32
canary 42ab0048ad
12,8gb
533.86s user 82.91s system 889% cpu 1:09.36 total
534.25s user 79.95s system 889% cpu 1:09.05 total
mischnic/optimizations 2774fc5a3
12,7
520.29s user 81.71s system 881% cpu 1:08.31 total
512.83s user 78.11s system 887% cpu 1:06.58 total
```
