all: cleanup unused code, part 2 (#10670)

And enable U1000 check in staticcheck.

Updates #cleanup

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

control/controlclient/map.go

@@ -8,7 +8,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"net"
-	"net/netip"
 	"reflect"
 	"slices"
 	"sort"
@@ -86,7 +85,6 @@ type mapSession struct {
 	lastDomainAuditLogID   string
 	lastHealth             []string
 	lastPopBrowserURL      string
-	stickyDebug            tailcfg.Debug // accumulated opt.Bool values
 	lastTKAInfo            *tailcfg.TKAInfo
 	lastNetmapSummary      string // from NetworkMap.VeryConcise
 }
@@ -790,43 +788,3 @@ func (ms *mapSession) netmap() *netmap.NetworkMap {
 	}
 	return nm
 }
-
-func nodesSorted(v []*tailcfg.Node) bool {
-	for i, n := range v {
-		if i > 0 && n.ID <= v[i-1].ID {
-			return false
-		}
-	}
-	return true
-}
-
-func sortNodes(v []*tailcfg.Node) {
-	sort.Slice(v, func(i, j int) bool { return v[i].ID < v[j].ID })
-}
-
-func cloneNodes(v1 []*tailcfg.Node) []*tailcfg.Node {
-	if v1 == nil {
-		return nil
-	}
-	v2 := make([]*tailcfg.Node, len(v1))
-	for i, n := range v1 {
-		v2[i] = n.Clone()
-	}
-	return v2
-}
-
-var debugSelfIPv6Only = envknob.RegisterBool("TS_DEBUG_SELF_V6_ONLY")
-
-func filterSelfAddresses(in []netip.Prefix) (ret []netip.Prefix) {
-	switch {
-	default:
-		return in
-	case debugSelfIPv6Only():
-		for _, a := range in {
-			if a.Addr().Is6() {
-				ret = append(ret, a)
-			}
-		}
-		return ret
-	}
-}