Add ensureDelegationExist and ensureDelegationNotExist to the tests of staking compound

[chrisli30]

In the tests of #103, a pre-requisite function is missing from the tests,

• In compound tests, delegations need to exist before running
• In delegation tests, there should be no delegation set up before running

We need to create common functions, ensureDelegationExist and ensureDelegationNotExist for the above purposes.

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This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 7 days.