Remove "disable automatic shutdown"

[MetRonnie]

These changes partially address #3696

From the config proposal: [cylc]disable automatic shutdown -> obsolete

hjoliver on 9 Oct 2019
I think we can get rid of this item. The original intent was to make suites stay alive for ever, even if finished, so that users could see them in the GUI until explicitly shutting them down. But that is really not necessary, and may lead to forgotten zombie suites.

Requirements check-list

• I have read CONTRIBUTING.md and added my name as a Code Contributor.
• Contains logically grouped changes (else tidy your branch by rebase).
• Does not contain off-topic changes (use other PRs for other changes).
• Does not need tests.
• No changelog entry needed (entry will be written after conf: ensure all proposed changes have been enacted #3696 is closed)
• No documentation update required (docs will be updated after conf: ensure all proposed changes have been enacted #3696 is closed)
• No dependency changes.

[MetRonnie]

As far as I can tell this will still perform the objective of the test: "Test no stall when task pool has succeeded tasks only."

[hjoliver]

Looks good, but tests/f/events/31... can be removed; it doesn't really do anything useful now because the scheduler will just shut down as soon as the lone tasks succeeds (and in SoD there are no succeeded tasks kept in the task pool anyway).

[hjoliver]

Meh, to save time I've pushed the test deletion to your branch. One review will do. All the other tests already passed.

[hjoliver]

(Also fixed a conflict in a deprecations test, passed in my environment).

[MetRonnie]

@hjoliver As you seem to be on a config changes roll, you can review #3943 too if you like 😋