Fix benchmark with new XCM::V3 MAX_INSTRUCTIONS_TO_DECODE (#2515)

* Fix benchmark with new XCM::V3 `MAX_INSTRUCTIONS_TO_DECODE` (#2514)

* Fix benchmark with new XCM::V3 MAX_INSTRUCTIONS_TO_DECODE

* Small refactor

* `ClearOrigin` replaced by ExpectPallet

* Doc

* Spellcheck

* Fixes and pr reviews
# Conflicts:
#	bin/millau/runtime/src/lib.rs
#	bin/runtime-common/src/messages_benchmarking.rs

* Fix closure stuff