net/art: add debug hooks to strideTable

Updates #7781

Signed-off-by: David Anderson <danderson@tailscale.com>

net/art/stride_table.go

@@ -13,6 +13,11 @@ import (
 	"strings"
 )
 
+const (
+	debugStrideInsert = false
+	debugStrideDelete = false
+)
+
 // strideEntry is a strideTable entry.
 type strideEntry[T any] struct {
 	// prefixIndex is the prefixIndex(...) value that caused this stride entry's

net/art/stride_table_test.go

@@ -52,12 +52,16 @@ func TestStrideTableInsert(t *testing.T) {
 	slow := slowTable[int]{pfxs}
 	fast := strideTable[int]{}
 
+	if debugStrideInsert {
 		t.Logf("slow table:\n%s", slow.String())
+	}
 
 	for _, pfx := range pfxs {
 		fast.insert(pfx.addr, pfx.len, pfx.val)
+		if debugStrideInsert {
 			t.Logf("after insert %d/%d:\n%s", pfx.addr, pfx.len, fast.tableDebugString())
 		}
+	}
 
 	for i := 0; i < 256; i++ {
 		addr := uint8(i)
@@ -122,12 +126,16 @@ func TestStrideTableDelete(t *testing.T) {
 	slow := slowTable[int]{pfxs}
 	fast := strideTable[int]{}
 
+	if debugStrideDelete {
 		t.Logf("slow table:\n%s", slow.String())
+	}
 
 	for _, pfx := range pfxs {
 		fast.insert(pfx.addr, pfx.len, pfx.val)
+		if debugStrideDelete {
 			t.Logf("after insert %d/%d:\n%s", pfx.addr, pfx.len, fast.tableDebugString())
 		}
+	}
 
 	toDelete := pfxs[:50]
 	for _, pfx := range toDelete {