athenaHLT: Fixes for Python3

Call PyOS_AfterFork() in the child process. This seems to be required in Python 3. Otherwise the child hangs (ATR-20871).

Also fix an integer division problem in TrigByteStreamTools.

This merge request affects 2 packages:

• HLT/Trigger/TrigControl/TrigPSC
• Trigger/TrigTools/TrigByteStreamTools

Adding @bernius ,@wiedenma ,@rbielski ,@fwinkl as watchers

added Trigger master review-pending-level-1 labels

CI Result SUCCESS (hash ee23467b)

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 0
AthSimulation: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 9379]

Changes and CI look good. Approving.

Kira (L1)

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 21c7d9b5

added sweep:ignore label