Allow parallel execution of child nodes if only read locks are acquired

[leonard84]

fixes #2423

Overview

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Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes
• All continuous integration builds pass

[codecov]

Codecov Report

Merging #2515 (463465e) into main (0be0e78) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main    #2515      +/-   ##
============================================
+ Coverage     90.52%   90.55%   +0.03%     
- Complexity     4623     4632       +9     
============================================
  Files           403      403              
  Lines         11460    11468       +8     
  Branches        919      921       +2     
============================================
+ Hits          10374    10385      +11     
+ Misses          808      806       -2     
+ Partials        278      277       -1     

Impacted Files	Coverage Δ	Complexity Δ
...rm/engine/support/hierarchical/NodeTreeWalker.java	100.00% <100.00%> (ø)	21.00 <7.00> (+7.00)
...piter/engine/descriptor/JupiterTestDescriptor.java	90.90% <0.00%> (+1.51%)	27.00% <0.00%> (+1.00%)
...tform/engine/support/hierarchical/LockManager.java	100.00% <0.00%> (+8.00%)	13.00% <0.00%> (+1.00%)

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[marcphilipp]

@leonard84 Could you please add an entry to the release notes?