[pipelines] OptimizerEarlyEPCallbacks for ThinLTO prelink

Similar to OptimizerLastEPCallbacks workaround
added D96320.

Probably NFC as-is, I don't see anything hooked with this callbacks yet,
but I we are looking to move sanitizers.

Reviewed By: aeubanks, MaskRay

Differential Revision: https://reviews.llvm.org/D133333