[CI] Add bootnode checking CI jobs (#6889)

* Add check_bootnode script and github action

* fix mktemp for linux machines

* Update check_bootnodes.sh

show logs to see what's going wrong

* fix ephemeral ports and fetch polkadot

* fix check-bootnodes.yml

* increase node spawn holdoff

* disable fail-fast

* refactor, separate out check_bootnodes and make it posix-compliant

* add new job for detecting new bootnodes

* fix check-bootnodes.yml

* only check all bootnodes on release

* Add test bad bootnode

REVERT ME before merging PR. Should cause the test to fail, then
when we remove it, we should succeed. Sadly doesn't account for a
new successful bootnode, should ask if we have one we can use for
testing.

* fix paths

* fix paths and git... hopefully

* this better work...

* fix

* test

* last test

* Revert "Add test bad bootnode"

This reverts commit 540dd9754a1f8e2d3fef33f7f5a033b8c2aa4dcb.

* Update check_bootnodes.sh

* optimisations

Begin polling the RPC node right after spawning, allowing us to break
early on detecting peers

* increase holdoff to 5 seconds

* dont delete chainspec til we kill the node

* Update check-bootnodes.yml

* Remove checking bootnodes on pushing of this branch

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Co-authored-by: parity-processbot <>