Elastic scaling: use an assumed `CoreIndex` in `candidate-backing` (#3229)
First step in implementing https://github.com/paritytech/polkadot-sdk/issues/3144 ### Summary of changes - switch statement `Table` candidate mapping from `ParaId` to `CoreIndex` - introduce experimental `InjectCoreIndex` node feature. - determine and assume a `CoreIndex` for a candidate based on statement validator index. If the signature is valid it means validator controls the validator that index and we can easily map it to a validator group/core. - introduce a temporary provisioner fix until we fully enable elastic scaling in the subystem. The fix ensures we don't fetch the same backable candidate when calling `get_backable_candidate` for each core. TODO: - [x] fix backing tests - [x] fix statement table tests - [x] add new test --------- Signed-off-by:Andrei Sandu <[email protected]> Signed-off-by:
alindima <[email protected]> Co-authored-by: