Add flag to disable FunctorCache in lhcb-master
Fix the FunctorCache disabling in lhcb-master
lhcb/Rec!4549 (merged) deprecated the old LOKI_BUILD_FUNCTOR_CACHE flag and introduced the new BUILD_FUNCTOR_CACHE flag. Since this change is only merged into the master branch and not into the 2024/2025-patches branches, both flags are needed to ensure that the functor cache is correctly disabled.
FYI: @rmatev