Deprecate syncUninterruptibly() and awaitRequestNUninterruptibly() in tests

[Krupskis]

Motivation:
Currently netty's syncUninterruptibly() and
awaitRequestNUninterruptibly() do not
propogate InterruptedException, meaning that jUnit5 is not
able to stop timeouted tests.

Modifications:

• change the uses of syncUninterruptibly() to sync()
• on safeSync() use Callable instead of Runnable, because
  Runnable is unable to throw exception;
• Change all usages of awaitRequestNUninterruptibly()
  to awaitRequestN();
• add @Deprecated to awaitRequestNUninterruptibly();

Result:
InterruptedException is no longer silently discarded,
meaning jUnit5 will be able to abort the timeouted test.

Related to #1684.

Questions from my side:

1. Why the N in awaitRequestN()?
2. Doesn’t safeClose() in HttpsProxyTest also not
   Propagate the InterruptedException, which might
   result in timeouts as well?
3. I couldn't figure out what the function of
   safeSync(), so I changed it to use Callable,
   could someone explain what it does in
   a bit more in depth?

[idelpivnitskiy]

Great change! Thank you @Krupskis!
One comment, then LGTM.

Remaining answers:

1. Why the N in awaitRequestN()?

Reactive Streams specification defines a method void request(long n) for Subscription.
The word "request" is used in different contexts, we decided to add N at the end to highlight it's related to requesting N elements for Reactive Streams. Just found this convenient, no other reasons.

3. I couldn't figure out what the function of safeSync(), so I changed it to use Callable, could someone explain what it does in a bit more in depth?

Good question! Let's take an example from StreamObserverTest:

    @AfterEach
    void teardown() throws Exception {
        safeSync(() -> serverAcceptorChannel.close().sync());
        safeSync(() -> serverEventLoopGroup.shutdownGracefully(0, 0, MILLISECONDS).sync());
        safeClose(client);
    }

Without safeSync, if the first line throws, we will never close serverEventLoopGroup and client. safeSync helps to make sure we continue teardown even if any of the lines throw an exeption.

[idelpivnitskiy]

2. Doesn’t safeClose() in HttpsProxyTest also not Propagate the InterruptedException, which might result in timeouts as well?

Good catch! You are right. Also, before re-throwing the InterruptedException, we should reset interrupted flag:

Thread.currentThread().interrupt();
throw e;

[Krupskis]

Good catch, forgot that it resets the value :)

[Krupskis]

@idelpivnitskiy thanks for the answers, all is clear now.

[idelpivnitskiy]

Thank you @Krupskis!