all: cleanup unused code, part 1 (#10661)

Run `staticcheck` with `U1000` to find unused code. This cleans up about
a half of it. I'll do the other half separately to keep PRs manageable.

Updates #cleanup

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>

tka/scenario_test.go

@@ -5,9 +5,7 @@ package tka
 
 import (
 	"crypto/ed25519"
-	"fmt"
 	"sort"
-	"strings"
 	"testing"
 )
 
@@ -100,22 +98,6 @@ func (s *scenarioTest) mkNodeWithForks(name string, signWithDefault bool, chains
 	return n
 }
 
-func aumsToNames(n *scenarioNode, aums []AUM) string {
-	out := make([]string, 0, len(aums))
-outer:
-	for _, a := range aums {
-		for name, candidate := range n.AUMs {
-			if candidate.Hash() == a.Hash() {
-				out = append(out, name)
-				continue outer
-			}
-		}
-		out = append(out, fmt.Sprintf("%x", a.Hash()))
-	}
-
-	return strings.Join(out, ",")
-}
-
 func (s *scenarioTest) syncBetween(n1, n2 *scenarioNode) error {
 	o1, err := n1.A.SyncOffer(n1.storage)
 	if err != nil {