core/state: skip redundant trie Commit for Verkle in stateObject.commit (#34021)

## Summary

**Bug fix.** In Verkle mode, all state objects share a single unified
trie (`OpenStorageTrie` returns `self`). During `stateDB.commit()`, the
main account trie is committed via `s.trie.Commit(true)`, which calls
`CollectNodes` to traverse and serialize the entire tree. However, each
dirty account's `obj.commit()` also calls `s.trie.Commit(false)` on the
**same trie object**, redundantly traversing and serializing the full
tree once per dirty account.

With N dirty accounts per block, this causes **N+1 full-tree
traversals** instead of 1. On a write-heavy workload (2250 SSTOREs),
this produces ~131 GB of allocations per block from duplicate NodeSet
creation and serialization. It also causes a latent data race from N+1
goroutines concurrently calling `CollectNodes` on shared `InternalNode`
objects.

This commit adds an `IsVerkle()` early return in `stateObject.commit()`
to skip the redundant `trie.Commit()` call.

## Benchmark (AMD EPYC 48-core, 500K entries, `--benchtime=10s
--count=3`)

| Metric | Baseline | Fixed | Delta |
|--------|----------|-------|-------|
| Approve (Mgas/s) | 4.16 ± 0.37 | **220.2 ± 10.1** | **+5190%** |
| BalanceOf (Mgas/s) | 966.2 ± 8.1 | 971.0 ± 3.0 | +0.5% |
| Allocs/op (approve) | 136.4M | 792K | **-99.4%** |

Resolves the TODO in statedb.go about the account trie commit being
"very heavy" and "something's wonky".

---------

Co-authored-by: Guillaume Ballet <3272758+gballet@users.noreply.github.com>

core/state/state_object.go

@@ -474,6 +474,14 @@ func (s *stateObject) commit() (*accountUpdate, *trienode.NodeSet, error) {
 		s.origin = s.data.Copy()
 		return op, nil, nil
 	}
+	// In Verkle/binary trie mode, all state objects share one unified trie.
+	// The main account trie commit in stateDB.commit() already calls
+	// CollectNodes on this trie, so calling Commit here again would
+	// redundantly traverse and serialize the entire tree per dirty account.
+	if s.db.GetTrie().IsVerkle() {
+		s.origin = s.data.Copy()
+		return op, nil, nil
+	}
 	root, nodes := s.trie.Commit(false)
 	s.data.Root = root
 	s.origin = s.data.Copy()