Revert part of GCC warning fix to fix debug build.

The typedef is used inside the DEBUG(), and apparently can't be moved
inside of it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196528 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineBlockPlacement.cpp

@@ -949,6 +949,7 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
   BlockChain &FunctionChain = *BlockToChain[&F.front()];
   buildChain(&F.front(), FunctionChain, BlockWorkList);
 
+  typedef SmallPtrSet<MachineBasicBlock *, 16> FunctionBlockSetType;
   DEBUG({
     // Crash at the end so we get all of the debugging output first.
     bool BadFunc = false;