[v18] port bound keypair tests to new join service

lib/auth/join_bound_keypair_test.go

@@ -99,6 +99,9 @@ func parseJoinState(t *testing.T, state []byte) *boundkeypair.JoinState {
 	return &doc
 }
 
+// TODO(nklaassen): DELETE IN 20 when the legacy join service is removed, this
+// test is superceded by lib/join.TestJoinBoundKeypair which exercises the new
+// join service.
 func TestServer_RegisterUsingBoundKeypairMethod(t *testing.T) {
 	t.Parallel()
 
@@ -944,6 +947,9 @@ func testExtractBotParamsFromCerts(t require.TestingT, certs *proto.Certs) (stri
 	return ident.BotInstanceID, ident.Generation
 }
 
+// TODO(nklaassen): DELETE IN 20 when the legacy join service is removed, this
+// test is superceded by lib/join.TestJoinBoundKeypair_GenerationCounter which
+// exercises the new join service.
 func TestServer_RegisterUsingBoundKeypairMethod_GenerationCounter(t *testing.T) {
 	t.Parallel()
 
@@ -1148,6 +1154,9 @@ func TestServer_RegisterUsingBoundKeypairMethod_GenerationCounter(t *testing.T)
 	}, 5*time.Second, 100*time.Millisecond)
 }
 
+// TODO(nklaassen): DELETE IN 20 when the legacy join service is removed, this
+// test is superceded by lib/join.TestJoinBoundKeypair_JoinStateFailure which
+// exercises the new join service.
 func TestServer_RegisterUsingBoundKeypairMethod_JoinStateFailure(t *testing.T) {
 	// This tests that join state verification will trigger a lock if the
 	// original client and a secondary client both attempt to recover in
@@ -1304,6 +1313,9 @@ func TestServer_RegisterUsingBoundKeypairMethod_JoinStateFailure(t *testing.T) {
 	}, 5*time.Second, 100*time.Millisecond)
 }
 
+// TODO(nklaassen): DELETE IN 20 when the legacy join service is removed, this
+// test is superceded by lib/join.TestJoinBoundKeypair_JoinStateFailureDuringRenewal
+// which exercises the new join service.
 func TestServer_RegisterUsingBoundKeypairMethod_JoinStateFailureDuringRenewal(t *testing.T) {
 	// Similar to _JoinStateFailure above, this exercises the case where the
 	// original client still has valid certs and isn't attempting a recovery of