See #31944
There is deadlock in concurrent invocation on `cache.DoWait()`. Suppose
2 callers are calling `DoWait` concurrently, the notification for cache
wait queue may be limited to just 1 caller's occupation instead of them
combined.
To fix this issue, this patch is trying to notify all waiters in queue.
Signed-off-by: Ted Xu <ted.xu@zilliz.com>