…sets (#3142)

This fix aims to solve an issue in Kusama that resulted in failed
reserve asset transfers.

During multi-hop XCMs, like reserve asset transfers where the reserve is
not the sender nor the destination, but a third remote chain, the origin
is not available to pay for delivery fees out of their account directly,
so delivery fees should be paid out of transferred assets.

This commit also adds an xcm-emulator regression test that validates
this scenario is now working.

Signed-off-by: Adrian Catangiu <adrian@parity.io>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>

Moved from: paritytech/polkadot#6951

closes #490

- [x] update cumulus

---
This PR introduces transactional processing of certain xcm instructions.
For the list of instructions checkout
#490. The transactional
processing is implemented as an xcm-executor config item. The two
implementations in this PR are `FrameTransactionalProcessor` and `()`.
The `()` implementation does no transactional processing. Each
implementation of the `ProcessTransaction` trait has an
`IS_TRANSACTIONAL` const that tells the XCVM if transactional processing
is actually implemented. If Transactional processing is implemented,
changes to touched registers should also be rolled back to prevent
inconsistencies.

Note for reviewers:
Check out the following safety assumption:
https://github.com/paritytech/polkadot-sdk/pull/1222/files#diff-4effad7d8c1c9de19fd27e18661cbf2128c8718f3b2420a27d2f816e0749ea53R30

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Co-authored-by: Keith Yeung <kungfukeith11@gmail.com>
Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>
Co-authored-by: command-bot <>

For some reason original PR passed CI - when it shouldn't have. Fix
`pallet-xcm` test benchmarks.

cc paritytech/ci_cd#900

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Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Dónal Murray <donal.murray@parity.io>
Co-authored-by: Bastian Köcher <info@kchr.de>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: command-bot <>