Small speed up to frequently called datetime functions (#85399)

tests/conftest.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 import asyncio
 from collections.abc import AsyncGenerator, Callable, Generator
 from contextlib import asynccontextmanager
+import datetime
 import functools
 import gc
 import itertools
@@ -78,6 +79,14 @@ asyncio.set_event_loop_policy(runner.HassEventLoopPolicy(False))
 asyncio.set_event_loop_policy = lambda policy: None
 
 
+def _utcnow():
+    """Make utcnow patchable by freezegun."""
+    return datetime.datetime.now(datetime.timezone.utc)
+
+
+dt_util.utcnow = _utcnow
+
+
 def pytest_addoption(parser):
     """Register custom pytest options."""
     parser.addoption("--dburl", action="store", default="sqlite://")