all: use Go 1.21 slices, maps instead of x/exp/{slices,maps}

Updates #8419

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/dns/manager.go

@@ -12,11 +12,11 @@ import (
 	"net"
 	"net/netip"
 	"runtime"
+	"slices"
 	"strings"
 	"sync/atomic"
 	"time"
 
-	"golang.org/x/exp/slices"
 	"tailscale.com/health"
 	"tailscale.com/net/dns/resolver"
 	"tailscale.com/net/netmon"

net/dns/recursive/recursive.go

@@ -10,11 +10,11 @@ import (
 	"fmt"
 	"net"
 	"net/netip"
+	"slices"
 	"strings"
 	"time"
 
 	"github.com/miekg/dns"
-	"golang.org/x/exp/slices"
 	"tailscale.com/envknob"
 	"tailscale.com/net/netns"
 	"tailscale.com/types/logger"

net/dns/recursive/recursive_test.go

@@ -15,8 +15,9 @@ import (
 	"testing"
 	"time"
 
+	"slices"
+
 	"github.com/miekg/dns"
-	"golang.org/x/exp/slices"
 	"tailscale.com/envknob"
 	"tailscale.com/tstest"
 )

net/dnsfallback/dnsfallback.go

@@ -19,11 +19,11 @@ import (
 	"net/url"
 	"os"
 	"reflect"
+	"slices"
 	"sync/atomic"
 	"time"
 
 	"go4.org/netipx"
-	"golang.org/x/exp/slices"
 	"tailscale.com/atomicfile"
 	"tailscale.com/envknob"
 	"tailscale.com/net/dns/recursive"

net/tsaddr/tsaddr.go

@@ -8,10 +8,10 @@ import (
 	"encoding/binary"
 	"errors"
 	"net/netip"
+	"slices"
 	"sync"
 
 	"go4.org/netipx"
-	"golang.org/x/exp/slices"
 	"tailscale.com/net/netaddr"
 )
 

net/tstun/wrap.go

@@ -12,6 +12,7 @@ import (
 	"net/netip"
 	"os"
 	"reflect"
+	"slices"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -20,7 +21,6 @@ import (
 	"github.com/tailscale/wireguard-go/device"
 	"github.com/tailscale/wireguard-go/tun"
 	"go4.org/mem"
-	"golang.org/x/exp/slices"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 	"tailscale.com/disco"
 	"tailscale.com/net/connstats"