util/cmpx: delete now that we're using Go 1.22

Updates #11058

Change-Id: I09dea8e86f03ec148b715efca339eab8b1f0f644
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/dnscache/messagecache.go

@@ -4,6 +4,7 @@
 package dnscache
 
 import (
+	"cmp"
 	"encoding/binary"
 	"errors"
 	"fmt"
@@ -13,7 +14,6 @@ import (
 
 	"github.com/golang/groupcache/lru"
 	"golang.org/x/net/dns/dnsmessage"
-	"tailscale.com/util/cmpx"
 )
 
 // MessageCache is a cache that works at the DNS message layer,
@@ -60,7 +60,7 @@ func (c *MessageCache) Flush() {
 // pruneLocked prunes down the cache size to the configured (or
 // default) max size.
 func (c *MessageCache) pruneLocked() {
-	max := cmpx.Or(c.cacheSizeSet, 500)
+	max := cmp.Or(c.cacheSizeSet, 500)
 	for c.cache.Len() > max {
 		c.cache.RemoveOldest()
 	}

net/netcheck/netcheck.go

@@ -6,6 +6,7 @@ package netcheck
 
 import (
 	"bufio"
+	"cmp"
 	"context"
 	"crypto/tls"
 	"errors"
@@ -41,7 +42,6 @@ import (
 	"tailscale.com/types/opt"
 	"tailscale.com/types/views"
 	"tailscale.com/util/clientmetric"
-	"tailscale.com/util/cmpx"
 	"tailscale.com/util/mak"
 )
 
@@ -447,7 +447,7 @@ func makeProbePlan(dm *tailcfg.DERPMap, ifState *interfaces.State, last *Report)
 				do6 = false
 			}
 			n := reg.Nodes[try%len(reg.Nodes)]
-			prevLatency := cmpx.Or(
+			prevLatency := cmp.Or(
 				last.RegionLatency[reg.RegionID]*120/100,
 				defaultActiveRetransmitTime)
 			delay := time.Duration(try) * prevLatency
@@ -1602,7 +1602,7 @@ func (rs *reportState) runProbe(ctx context.Context, dm *tailcfg.DERPMap, probe
 // proto is 4 or 6
 // If it returns nil, the node is skipped.
 func (c *Client) nodeAddr(ctx context.Context, n *tailcfg.DERPNode, proto probeProto) (ap netip.AddrPort) {
-	port := cmpx.Or(n.STUNPort, 3478)
+	port := cmp.Or(n.STUNPort, 3478)
 	if port < 0 || port > 1<<16-1 {
 		return
 	}