all: remove some Debug fields, NetworkMap.Debug, Reconfig Debug arg

Updates #8923

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

types/netmap/netmap.go

@@ -8,7 +8,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/netip"
-	"reflect"
 	"strings"
 	"time"
 
@@ -53,9 +52,6 @@ type NetworkMap struct {
 	// between updates and should not be modified.
 	DERPMap *tailcfg.DERPMap
 
-	// Debug knobs from control server for debug or feature gating.
-	Debug *tailcfg.Debug
-
 	// ControlHealth are the list of health check problems for this
 	// node from the perspective of the control plane.
 	// If empty, there are no known problems from the control plane's
@@ -182,10 +178,6 @@ func (nm *NetworkMap) printConciseHeader(buf *strings.Builder) {
 		}
 	}
 	fmt.Fprintf(buf, " u=%s", login)
-	if nm.Debug != nil {
-		j, _ := json.Marshal(nm.Debug)
-		fmt.Fprintf(buf, " debug=%s", j)
-	}
 	fmt.Fprintf(buf, " %v", nm.Addresses)
 	buf.WriteByte('\n')
 }
@@ -204,7 +196,7 @@ func (a *NetworkMap) equalConciseHeader(b *NetworkMap) bool {
 			return false
 		}
 	}
-	return (a.Debug == nil && b.Debug == nil) || reflect.DeepEqual(a.Debug, b.Debug)
+	return true
 }
 
 // printPeerConcise appends to buf a line representing the peer p.

types/netmap/netmap_test.go

@@ -59,22 +59,6 @@ func TestNetworkMapConcise(t *testing.T) {
 			},
 			want: "netmap: self: [AQEBA] auth=machine-unknown u=? []\n [AgICA] D2                 :    192.168.0.100:12     192.168.0.100:12354\n [AwMDA] D4                 :       10.2.0.100:12        10.1.0.100:12345\n",
 		},
-		{
-			name: "debug_non_nil",
-			nm: &NetworkMap{
-				NodeKey: testNodeKey(1),
-				Debug:   &tailcfg.Debug{},
-			},
-			want: "netmap: self: [AQEBA] auth=machine-unknown u=? debug={} []\n",
-		},
-		{
-			name: "debug_values",
-			nm: &NetworkMap{
-				NodeKey: testNodeKey(1),
-				Debug:   &tailcfg.Debug{SleepSeconds: 1.5},
-			},
-			want: "netmap: self: [AQEBA] auth=machine-unknown u=? debug={\"SleepSeconds\":1.5} []\n",
-		},
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			var got string