benchmark cli: pallet list returns instance names

[muharem]

benchmark pallet --list returns instance names, result <pallet name>, <extrinsic>, <instance name>.

questions:

• can this break anything? because of this risk the instance name appears at the end, even though it looks more logical to have it after the name
• some names resolves as SystemBench::<Runtime>, there is also an example how to fix it

[muharem]

or we can put the new field under some --output flag