Support starting abandoned child after parent workflow is closed

[yycptt]

Is your feature request related to a problem? Please describe. Currently after parent workflow is closed, if child is not started yet (meaning child started event not recorded), child start will be skipped even if the parent close policy is abandon. Due to this reason, user needs to explicitly wait for the started event in their workflow before completing it.

Describe the solution you'd like https://github.com/temporalio/temporal/blob/master/service/history/transferQueueActiveTaskExecutor.go#L687 https://github.com/temporalio/temporal/blob/master/service/history/transferQueueStandbyTaskExecutor.go#L415

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context

[mfateev]

This applies to signalExternalWorkflow as well.