revert some WIP code

Author: trentxintong

lib/SILOptimizer/Transforms/DeadStoreElimination.cpp

@@ -434,9 +434,6 @@ class DSEContext {
 } // end anonymous namespace
 
 void BlockState::initReturnBlock(DSEContext &Ctx) {
-  if (DisableLocalDSE)
-    return;
-
   auto *EA = Ctx.getEA();
   auto *Fn = Ctx.getFn();
   std::vector<LSLocation> &LocationVault = Ctx.getLocationVault();