Refactor all instances of `typedef y x` to the C++11 `using x = y` syntax.

src/IceCfg.cpp

Index: src/IceCfg.cpp
diff --git a/src/IceCfg.cpp b/src/IceCfg.cpp
index 0b2aa9442bc2981650feeda0337efea47f9ae717..c068c44b342e5e07b0d9c3b3a16607a50fbcfacc 100644
--- a/src/IceCfg.cpp
+++ b/src/IceCfg.cpp
@@ -311,7 +311,7 @@ void Cfg::advancedPhiLowering() {
 void Cfg::reorderNodes() {
   // TODO(ascull): it would be nice if the switch tests were always followed
   // by the default case to allow for fall through.
-  typedef std::list<CfgNode *> PlacedList;
+  using PlacedList = std::list<CfgNode *>;
   PlacedList Placed;      // Nodes with relative placement locked down
   PlacedList Unreachable; // Unreachable nodes
   PlacedList::iterator NoPlace = Placed.end();