[NewPM] Fix CGSCCOptimizerLateEPCallbacks place in pipeline

CGSCCOptimizerLateEPCallbacks are supposed to be run before the function
simplification pipeline, like in the legacy PM and as specified in the
comments for registerCGSCCOptimizerLateEPCallback().

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D93871