async_hooks: only set up hooks if used

PR-URL: #13177
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Andreas Madsen <amwebdk@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/async_hooks.js

@@ -49,12 +49,7 @@ const before_symbol = Symbol('before');
 const after_symbol = Symbol('after');
 const destroy_symbol = Symbol('destroy');
 
-// Setup the callbacks that node::AsyncWrap will call when there are hooks to
-// process. They use the same functions as the JS embedder API.
-async_wrap.setupHooks({ init,
-                        before: emitBeforeN,
-                        after: emitAfterN,
-                        destroy: emitDestroyN });
+let setupHooksCalled = false;
 
 // Used to fatally abort the process if a callback throws.
 function fatalError(e) {
@@ -103,6 +98,16 @@ class AsyncHook {
     if (hooks_array.includes(this))
       return;
 
+    if (!setupHooksCalled) {
+      setupHooksCalled = true;
+      // Setup the callbacks that node::AsyncWrap will call when there are
+      // hooks to process. They use the same functions as the JS embedder API.
+      async_wrap.setupHooks({ init,
+                              before: emitBeforeN,
+                              after: emitAfterN,
+                              destroy: emitDestroyN });
+    }
+
     // createHook() has already enforced that the callbacks are all functions,
     // so here simply increment the count of whether each callbacks exists or
     // not.