ipn/ipnlocal, engine: avoid runtime/pprof with two usages of ts_omit_debug

Saves 258 KB.

Updates #12614

Change-Id: I37c2f7f916480e3534883f338de4c64d08f7ef2b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

wgengine/watchdog.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build !js
+//go:build !js && !ts_omit_debug
 
 package wgengine
 

wgengine/watchdog_js.go

@@ -1,17 +0,0 @@
-// Copyright (c) Tailscale Inc & AUTHORS
-// SPDX-License-Identifier: BSD-3-Clause
-
-//go:build js
-
-package wgengine
-
-import "tailscale.com/net/dns/resolver"
-
-type watchdogEngine struct {
-	Engine
-	wrap Engine
-}
-
-func (e *watchdogEngine) GetResolver() (r *resolver.Resolver, ok bool) {
-	return nil, false
-}

wgengine/watchdog_omit.go

@@ -0,0 +1,8 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build js || ts_omit_debug
+
+package wgengine
+
+func NewWatchdog(e Engine) Engine { return e }