Revert "[semantic-arc] Rename isWrittenTo -> isLoadGuaranteedByStorage."

This reverts commit dbf84f3.

I closed the PR, but swift-ci merged anyways. The change was just a rename.

Author: gottesmm

lib/SILOptimizer/Mandatory/SemanticARCOpts.cpp

@@ -191,9 +191,7 @@ struct SemanticARCOptVisitor
   bool visitBeginBorrowInst(BeginBorrowInst *bbi);
   bool visitLoadInst(LoadInst *li);
 
-  /// Return true if all of load insts destroy_value users are within the
-  /// guaranteed lifetime of the storage that is being loaded from.
-  bool isLoadGuaranteedByStorage(LoadInst *li);
+  bool isWrittenTo(LoadInst *li);
 
   bool processWorklist();
 
@@ -716,7 +714,7 @@ class StorageGuaranteesLoadVisitor
 };
 } // namespace
 
-bool SemanticARCOptVisitor::isLoadGuaranteedByStorage(LoadInst *load) {
+bool SemanticARCOptVisitor::isWrittenTo(LoadInst *load) {
   StorageGuaranteesLoadVisitor visitor(*this, load);
   return visitor.doIt();
 }
@@ -738,10 +736,9 @@ bool SemanticARCOptVisitor::visitLoadInst(LoadInst *li) {
   if (!isDeadLiveRange(li, destroyValues))
     return false;
 
-  // Then check if our address is guaranteed to never be written to within the
-  // lifetime of our loaded value. If so, we can convert the loaded value to be
-  // at +0 instead of +1.
-  if (isLoadGuaranteedByStorage(li))
+  // Then check if our address is ever written to. If it is, then we
+  // can not use the load_borrow.
+  if (isWrittenTo(li))
     return false;
 
   // Ok, we can perform our optimization. Convert the load [copy] into a