Address ATR-20334 with additional mutex in TDT cache

Switches mutex -> recursive_mutex (so can nest mutex locks), add mutex in Trig::CacheGlobalMemory::createChainGroup

This merge request affects 1 package:

• Trigger/TrigAnalysis/TrigDecisionTool

added Trigger master review-pending-level-1 labels

CI Result SUCCESS

	Athena	AthSimulation
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-26751-2019-09-24-00-29
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 3519]

Tagging @tamartin for information.

Thanks @ponyisi - this is indeed a more thorough protection than the non-recursive mutex was offering.

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

merged

mentioned in commit 50bd1dc9

added sweep:ignore label