all: use various net/netip parse funcs directly

Mechanical change with perl+goimports.

Changed {Must,}Parse{IP,IPPrefix,IPPort} to their netip variants, then
goimports -d .

Finally, removed the net/netaddr wrappers, to prevent future use.

Updates #5162

Change-Id: I59c0e38b5fbca5a935d701645789cddf3d7863ad
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tstest/integration/integration_test.go

@@ -18,6 +18,7 @@ import (
 	"log"
 	"net/http"
 	"net/http/httptest"
+	"net/netip"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -830,7 +831,7 @@ func (n *testNode) AwaitIPs() []netaddr.IP {
 		addrs = make([]netaddr.IP, len(ipslice))
 
 		for i, ip := range ipslice {
-			netIP, err := netaddr.ParseIP(ip)
+			netIP, err := netip.ParseAddr(ip)
 			if err != nil {
 				t.Fatal(err)
 			}