GRADLE-2023 - Before iterating through the tasks to display for the task report, force the evaluation of all task dependencies (which may cause new tasks to be added).

This introduces TaskContainerInternal.actualize() that simply walks the graph of tasks which forces notional (e.g. a dependency on a task _name_) task dependencies to “materialize”. Doing this before generating the output for “tasks” prevents the task container being modified while being iterated.
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