Inheritance of team activation to child threads

[stephan]

If a team is activated for individual threads it would be great if newly spawned threads could inherit this activation. This should, of course, affect only those threads that are created from a thread for which the team is already active.

This is relevant in situations where one thread delegates a computation to a child thread, but conceptually both threads - parent and child - should be regarded as being the same context.

In order to support both variants - with and without inheritance of team activation - class Team should offer a boolean property inheritableActivation.

[stephan]

Tests are in

• 5.2.18-otjld-inheritable-team-activation-1 with inheritable activation
• 5.2.18-otjld-inheritable-team-activation-2 without inheritable activation

Implementation is in r19771 and r19772.