[FLINK-5016] [ci] Increase no output timeout to 10 mins

[uce]

Some heavy test suites occasionally have quite long running times on Travis, in which cases the no output timeout of 5 mins is too aggressive and incorrectly fails the build. This behaviour is meant to help debugging any deadlock situations we encounter on Travis.

This PR increases the no output timeout to 10 minutes. Since we're quite close to the maximum build times this will not detect anything that deadlocks in the last 10 minutes of the build after which Travis errors the build. I think that's OK.

Do you think increasing the timeout is OK or should we instead add some output to the heavy test suites or split them up?

/cc @tillrohrmann @aljoscha

[aljoscha]

I think it's fine to increase the timeout.

[StefanRRichter]

+1 for increased timeout.

[StephanEwen]

I think we should split up the tests that take so long into multiple files. That should do the trick as well.

For example, the EventTimeWindowCheckpointingITCase can simply have an abstract base class with the tests, and then three ITCase files with supply the state backend.

[uce]

Closing in favour of #2933.