[DSE] Remove commented-out InvisibleToCallerBeforeRet. (NFC)

This code was is a leftover from earlier changes and should be removed.

Author: fhahn

llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp

@@ -758,7 +758,6 @@ struct DSEState {
   SmallPtrSet<MemoryAccess *, 4> SkipStores;
   // Keep track of all of the objects that are invisible to the caller before
   // the function returns.
-  // SmallPtrSet<const Value *, 16> InvisibleToCallerBeforeRet;
   DenseMap<const Value *, bool> InvisibleToCallerBeforeRet;
   // Keep track of all of the objects that are invisible to the caller after
   // the function returns.