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/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
 	}