Sweeping !42977 from 21.6 to master. MGC tests, saving tgz outputs instead of event files

MGC tests, saving tgz outputs instead of event files

See merge request !42977 (merged)

added sweep:from 21.6 label

Adding original author @zmarshal as watcher.

This merge request affects 2 packages:

• Control/CxxUtils
• Generators/MadGraphControl

Affected files list will not be printed in this case

Adding @zmarshal ,@ssnyder ,@rbianchi as watchers

added Core Generators master review-pending-level-1 labels

CI Result SUCCESS (hash 294f71b4)

	Athena	AthSimulation	AthGeneration	AnalysisBase	AthAnalysis	DetCommon
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
AthGeneration: number of compilation errors 0, warnings 0
AnalysisBase: number of compilation errors 0, warnings 0
AthAnalysis: number of compilation errors 0, warnings 0
DetCommon: number of compilation errors 0, warnings 0
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 32561]

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

merged

mentioned in commit 8103c689

added sweep:ignore label