add unit tests for `actpool/queueworker.go`

[saitofun]

What would you like to be added

add unit tests for actpool/queueworker.go

• Add unit tests to cover L123-L124
• Add unit tests to cover L150
• Add unit tests to cover L239
• Add unit tests to cover L260
• Add unit tests to cover L302
• Add unit tests to cover L305-L309