test_runner: error on mocking an already mocked date

Fixes #55849

PR-URL: #55858
Reviewed-By: Jacob Smith <jacob@frende.me>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

lib/internal/test_runner/mock/mock_timers.js

@@ -335,6 +335,9 @@ class MockTimers {
   #createDate() {
     kMock ??= Symbol('MockTimers');
     const NativeDateConstructor = this.#nativeDateDescriptor.value;
+    if (NativeDateConstructor.isMock) {
+      throw new ERR_INVALID_STATE('Date is already being mocked!');
+    }
     /**
      * Function to mock the Date constructor, treats cases as per ECMA-262
      * and returns a Date object with a mocked implementation

test/parallel/test-runner-mock-timers-date.js

@@ -117,4 +117,11 @@ describe('Mock Timers Date Test Suite', () => {
     assert.strictEqual(fn.mock.callCount(), 0);
     clearTimeout(id);
   });
+
+  it((t) => {
+    t.mock.timers.enable();
+    t.test('should throw when a already-mocked Date is mocked', (t2) => {
+      assert.throws(() => t2.mock.timers.enable(), { code: 'ERR_INVALID_STATE' });
+    });
+  });
 });