AMQP-422 PublisherCallbackChannel: postpone close

JIRA: https://jira.spring.io/browse/AMQP-422

Add `stopSemaphore` and `closeTimeout` option to the `PublisherCallbackChannelImpl`
to postpone physical `close` until timeout or handlong for all pending confirms

Decrease `@Repeat` for `RabbitTemplatePerformanceIntegrationTests` for better build performance
See `ChannelN.waitForConfirmsOrDie` source code. It closes unconditionally and just only after that rethrows Exception. So our own `close()` code won't be reached.
Yes, I understand `InterruptedExeption` now. Thanks. But for me it looks like we should just ignore all those exceptions.
No?