Remove hardcoded execution count in benchmark functions

## Description

Found [staticcheck SA3001](https://staticcheck.dev/docs/checks/#SA3001) violation in `rawnode_test.go` :

```go
func benchmarkRawNodeImpl(b *testing.B, peers ...uint64) {
// ...
if debug {
b.N = 1
}
// ...
}
```

## Proposed Fix

Instead of hardcoding` b.N` in the function body, the execution count should be controlled via the `go test` command, e.g.:

```bash
go test -bench=BenchmarkRawNodeImpl -benchtime=1x
```

## Impact
This change ensures benchmark results are accurate and aligns with Go's testing best practices.

Open rawnode_test.go and inspect benchmarkRawNodeImpl for the hardcoded b.N assignment. Run the benchmark with go test -bench=BenchmarkRawNodeImpl -benchtime=1x, and verify that the execution count is controlled by the command rather than the function body; the staticcheck SA3001 violation should also be resolved.

Written by the indexing model from the issue text.