Fix infinite callback loop when used with async-solipsism

If the keepalive handler is called too soon, it reschedules itself. The
test used `now <= close_time`, which means that an exactly on-time
notification is treated as "too soon", causing an automatic
rescheduling. For real systems the time will eventually advance and
break the loop, but with async-solipsism, time doesn't advance until
there is some reason to sleep and the loop is infinite.

Closes aio-libs#10149.

aiohttp/web_protocol.py

@@ -487,7 +487,7 @@ def _process_keepalive(self) -> None:
         loop = self._loop
         now = loop.time()
         close_time = self._next_keepalive_close_time
-        if now <= close_time:
+        if now < close_time:
             # Keep alive close check fired too early, reschedule
             self._keepalive_handle = loop.call_at(close_time, self._process_keepalive)
             return