Revert "Add test for running children asynchronously"

This reverts commit 018690fe0a49dc5b3b24e2733b74d6d676f897a8.
Revert "Add patch from @spion to make nested-sync-noplan-noend pass"

This reverts commit 892c605f6efb713a6be8fe4475035921e312f576.
Add second @spion patch
add test for asynchronously adding subtests