util/uniq,types/lazy,*: delete code that's now in Go std

sync.OnceValue and slices.Compact were both added in Go 1.21.

cmp.Or was added in Go 1.22.

Updates #8632
Updates #11058

Change-Id: I89ba4c404f40188e1f8a9566c8aaa049be377754
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

version/print.go

@@ -7,11 +7,10 @@ import (
 	"fmt"
 	"runtime"
 	"strings"
-
-	"tailscale.com/types/lazy"
+	"sync"
 )
 
-var stringLazy = lazy.SyncFunc(func() string {
+var stringLazy = sync.OnceValue(func() string {
 	var ret strings.Builder
 	ret.WriteString(Short())
 	ret.WriteByte('\n')

version/prop.go

@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync"
 
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/lazy"
@@ -174,7 +175,7 @@ func IsUnstableBuild() bool {
 	})
 }
 
-var isDev = lazy.SyncFunc(func() bool {
+var isDev = sync.OnceValue(func() bool {
 	return strings.Contains(Short(), "-dev")
 })
 

version/version.go

@@ -9,6 +9,7 @@ import (
 	"runtime/debug"
 	"strconv"
 	"strings"
+	"sync"
 
 	tailscaleroot "tailscale.com"
 	"tailscale.com/types/lazy"
@@ -117,7 +118,7 @@ func (i embeddedInfo) commitAbbrev() string {
 	return i.commit
 }
 
-var getEmbeddedInfo = lazy.SyncFunc(func() embeddedInfo {
+var getEmbeddedInfo = sync.OnceValue(func() embeddedInfo {
 	bi, ok := debug.ReadBuildInfo()
 	if !ok {
 		return embeddedInfo{}