eliminated somewhat pointless parallelism (from 857da80611ab): usually hundreds of tasks with < 1ms each, also note that the enclosing join_theory happens within theory graph parallelism;
#hard-wired components
src/Tools/jEdit
src/Tools/Graphview
src/Tools/VSCode
src/HOL/Mirabelle
src/HOL/Mutabelle
src/HOL/Library/Sum_of_Squares
src/HOL/SPARK
src/HOL/Tools
src/HOL/Tools/ATP
src/HOL/TPTP