core, core/state: fold prefetcher elapsed into StateReadMs for BAL blocks

For BAL blocks AccountReads/StorageReads/CodeReads stay zero by design,
so the slow-block JSON state_read_ms read 0 — misleading to cross-client
consumers. Sum s.Prefetch (the prefetcher's elapsed time) into the field;
it's already zero on the pre-BAL path so the formula is unchanged there.

Also gofmt -w on reader.go and reader_eip_7928.go (trailing blank lines
left over from earlier cleanup).

core/blockchain_stats.go

@@ -222,7 +222,7 @@ func buildSlowBlockLog(s *ExecuteStats, block *types.Block) slowBlockLog {
 		},
 		Timing: slowBlockTime{
 			ExecutionMs: durationToMs(s.Execution),
-			StateReadMs: durationToMs(s.AccountReads + s.StorageReads + s.CodeReads),
+			StateReadMs: durationToMs(s.AccountReads + s.StorageReads + s.CodeReads + s.Prefetch),
 			StateHashMs: durationToMs(s.AccountHashes + s.AccountUpdates + s.StorageUpdates),
 			CommitMs:    durationToMs(max(s.AccountCommits, s.StorageCommits) + s.DatabaseCommit + s.BlockWrite),
 			TotalMs:     durationToMs(s.TotalTime),

core/state/reader.go

@@ -607,4 +607,3 @@ func (r *reader) GetStats() ReaderStats {
 		StateStats: r.GetStateStats(),
 	}
 }
-

core/state/reader_eip_7928.go

@@ -395,4 +395,3 @@ func (r *prefetchStateReader) GetStateStats() StateReaderStats {
 	}
 	return StateReaderStats{}
 }
-