Convert AFDO mutators to TransitionMutator

Convert afdoDepsMutator and afdoMutator to a TransitionMutator as a
step towards variants-on-demand.

This relands Ib05845455ccf43a07b3915a0d7b0a95896062f13 with a fix
to maintain the current behavior of not using AFDO variants for
dependencies of the linker static binary.

Bug: 319288033
Bug: 324141705
Test: afdo_test.go
Change-Id: I76e30021173fc5b7e9e1fa826039776eb3dc7b6e