Revert "Revert "[ConstHoist] Do not rebase single (or few) dependent constant""
This reverts commit bd7b44f35ee9fbe365eb25ce55437ea793b39346.
Reland r342994: disabled the optimization and explicitly enable it in test.
[ConstHoist] Do not rebase single (or few) dependent constant
If an instance (InsertionPoint or IP) of Base constant A has only one or few
rebased constants depending on it, do NOT rebase. One extra ADD instruction is
required to materialize each rebased constant, assuming A and the rebased have
the same materialization cost.
Differential Revision: https://reviews.llvm.org/D52243