Subzero: Implement InstList in terms of llvm::ilist<> .

src/IceOperand.cpp

Index: src/IceOperand.cpp
diff --git a/src/IceOperand.cpp b/src/IceOperand.cpp
index 8cf181afff3f67927c941fa8d004e23bfc39b2d7..7870d180b0b5e6458999f3818ff774775ab0726f 100644
--- a/src/IceOperand.cpp
+++ b/src/IceOperand.cpp
@@ -347,7 +347,8 @@ void VariablesMetadata::addNode(CfgNode *Node) {
     }
   }
 
-  for (Inst *I : Node->getInsts()) {
+  for (auto I = Node->getInsts().begin(), E = Node->getInsts().end(); I != E;
+       ++I) {
     if (I->isDeleted())
       continue;
     // Note: The implicit definitions (and uses) from InstFakeKill are