VariableListenerSupport.beforeVariableChanged() is severly slower (from CR1 to CR2) due to SortedMap usage

We're noticing a performance loss (sometimes up to 20% or 30% even) for use cases with chained planning variables, due to PLANNER-252, especially if no time windows or other shadow variables are in play (which benefit from a performance gain from PLANNER-252).

Deeper investigation shows that the SortedMap usage in VariableListenerSupport.beforeVariableChanged() takes a lot of time. See the 40 seconds spend on the get() method in the screenshot from JProfiler.
This is homberg1000 with incremental score calc, only LS with only change moves.