[#2086] Fix race which could produce NPE in AbstractNioUnsafe.finishConnect
Fix a regression in SslHandler where delegated tasks run in a different executor makes the session hang

- Fixes #2098
- Deprecate specifying an alternative Executor for delegated tasks for SslHandler
Remove the deprecated constructors in SslHandler
Move the reusable classes in netty-testsuite to main/java/src and deploy them
Fix a potential NPE due to the race between a connection attempt and its cancellation

- should fix #2086
Remove unnecessary test resource
Do not deploy an unused test jar
Remove unnecessary trailing newline
Merge remote-tracking branch: upstream/master