Graceful restart may cause crash, if no child slot is available for processors

[TaaviSannik]

Before rc2, if the server was gracefully restarted, then the server would create a separate table for the old children and clean it afterwards.

In rc2, this table was removed and all children from last run are stored in the main table.

This creates a problem, if there are many children alive while graceful restart occurs as the server is unable to add new processors to the child table.

For example: Server limit: 500 Server environments: 100 Children alive: 450

Graceful restart occurs, server starts to add new processors, adds the first 50 and then crashes as the child limit has been reached.