fix(ext/web): improve timers resolution for 0ms timeouts (#19212)

This commit changes the implementation of `ext/web` timers, by using
"op_void_async_deferred" for timeouts of 0ms.

0ms timeout is meant to be run at the end of the event loop tick and
currently Tokio timers that we use to back timeouts have at least 1ms
resolution. That means that 0ms timeout actually take >1ms. This
commit changes that and runs 0ms timeout at the end of the event
loop tick.

One consequence is that "unrefing" a 0ms timer will actually keep
the event loop alive (which I believe actually makes sense, the test
we had only worked because the timeout took more than 1ms).

Ref https://github.com/denoland/deno/issues/19034

cli/js/40_testing.js

@@ -50,7 +50,7 @@ function opSanitizerDelay() {
   return new Promise((resolve) => {
     setTimeout(() => {
       ArrayPrototypePush(opSanitizerDelayResolveQueue, resolve);
-    }, 0);
+    }, 1);
   });
 }