test_runner: mark mockTimers as stable

PR-URL: #55398
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Jake Yuesong Li <jake.yuesong@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

doc/api/test.md

@@ -2226,7 +2226,7 @@ added:
   - v18.19.0
 -->
 
-> Stability: 1 - Experimental
+> Stability: 2 - Stable
 
 Mocking timers is a technique commonly used in software testing to simulate and
 control the behavior of timers, such as `setInterval` and `setTimeout`,

lib/internal/test_runner/mock/mock_timers.js

@@ -27,9 +27,6 @@ const {
   validateStringArray,
 } = require('internal/validators');
 
-const {
-  emitExperimentalWarning,
-} = require('internal/util');
 const {
   AbortError,
   codes: {
@@ -133,10 +130,6 @@ class MockTimers {
   #clearInterval = FunctionPrototypeBind(this.#clearTimer, this);
   #clearImmediate = FunctionPrototypeBind(this.#clearTimer, this);
 
-  constructor() {
-    emitExperimentalWarning('The MockTimers API');
-  }
-
   #restoreSetImmediate() {
     ObjectDefineProperty(
       globalThis,