done (split in multiple diffs)

This can be split into several parts:

• Automate the stake contenders promotion via updatedBlockTip()
• Add the manual winners to the cache
• Vote on manual winners

@bot build-tsan

I still don't get what you're doing with the test. Look at the scriptnum10 purpose: it's an older implementation and is here to check the new implementation behaves the same.
Your change is breaking that expectation, deliberately. To check if this introduces a problem:

• You need to make sure opcodes are well covered by existing tests, including edge cases. I suggest you add these tests if they don't already exist in another diff to prove this one introduces no change in behavior.
• Just remove that legacy compliant test, which is no longer relevant exactly because of that change.

comment nit

remove getint32, change ScriptNum10::getint instead to support int64_t

fix a warning

One comment nit

improve behavior when cancelling a reindexing: remove alarming log, wipe the index and don't set the metadata flag to true when shutdown is requested during the process

Note: you can remove the note or un-bold it and move it to the bottom

Fix chainstate dependency

Build Bitcoin ABC Diffs / Diff Testing (preview-explorer) passed.
Preview is available at http://51.89.41.69:41257 for the next 60 minutes.

@bot preview-explorer