Supervisor transient workers restart strategy fix

[Michal Ptaszek]

Hi,

we have found the following inconsistency in the supervisor.erl code:
when supervisor's child restart strategy is set to transient and the child exits with reason shutdown, it is never restarted. 

The patches include fix for the issue and the test suite used for reproducing the error, and later, after patching, for verifying the correctness of the code. 

The patches are available here:
git fetch git@REDACTED:paulgray/otp.git
supervisor_transient_children_fix

Best regards,
Michal Ptaszek