Turbopack: inner graph tree shaking (#85973)
Alias "unused import removal"
Closes PACK-5782
Performance:
```
* 58fe2e2e377d877f51f91f50770310d2bbf20987 - WIP: enable by default
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 380.01s user 53.74s system 691% cpu 1:02.76 total
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 384.99s user 51.00s system 708% cpu 1:01.57 total
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 381.52s user 46.86s system 711% cpu 1:00.21 total
vs canary:
* f6c2d4913233109ea49256e587db9b7ce636a1a5 - Turbopack: add task_id_details feature (#84970)
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 374.87s user 48.47s system 760% cpu 55.662 total
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 379.18s user 50.27s system 700% cpu 1:01.28 total
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 370.39s user 45.93s system 726% cpu 57.305 total
pnpm next build --experimental-build-mode=compile > ~/Downloads/log.txt 2>&1 372.70s user 46.24s system 717% cpu 58.364 total
```
