ipn/{ipnlocal,localapi},wgengine{,/magicsock}: plumb health.Tracker

Down to 25 health.Global users. After this remains controlclient &
net/dns & wgengine/router.

Updates #11874
Updates #4136

Change-Id: I6dd1856e3d9bf523bdd44b60fb3b8f7501d5dc0d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/tailscaled/depaware.txt

@@ -358,6 +358,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/types/structs                                  from tailscale.com/control/controlclient+
         tailscale.com/types/tkatype                                  from tailscale.com/tka+
         tailscale.com/types/views                                    from tailscale.com/ipn/ipnlocal+
+        tailscale.com/util/cibuild                                   from tailscale.com/health
         tailscale.com/util/clientmetric                              from tailscale.com/control/controlclient+
         tailscale.com/util/cloudenv                                  from tailscale.com/net/dns/resolver+
         tailscale.com/util/cmpver                                    from tailscale.com/net/dns+

cmd/tailscaled/tailscaled.go

@@ -651,6 +651,7 @@ func tryEngine(logf logger.Logf, sys *tsd.System, name string) (onlyNetstack boo
 	conf := wgengine.Config{
 		ListenPort:    args.port,
 		NetMon:        sys.NetMon.Get(),
+		HealthTracker: sys.HealthTracker(),
 		Dialer:        sys.Dialer.Get(),
 		SetSubsystem:  sys.Set,
 		ControlKnobs:  sys.ControlKnobs(),