ci: Add integration test for s3 assume role

[Xuanwo]

PR #2687 added a feature that allowing users to assume role. We need to add a test to make sure it works as expected.

[Xuanwo]

cc @everpcpc, would you like to help take a look? Mabye we can set wif for this repo?

[everpcpc]

/assign me

[suyanhanx]

/assign me

Thanks and have fun!