Completely merge the implementation details of DomTree and PostDomTree.

Also, add a FIXME for a bug in PostDomTree calculation I noticed while writing this,


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42593 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/PostDominators.cpp b/lib/Analysis/PostDominators.cpp
index 0ca7388..f066f7a 100644
--- a/lib/Analysis/PostDominators.cpp
+++ b/lib/Analysis/PostDominators.cpp
@@ -16,7 +16,7 @@
 #include "llvm/Support/CFG.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SetOperations.h"
-#include "PostDominatorCalculation.h"
+#include "llvm/Analysis/DominatorInternals.h"
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//
@@ -47,7 +47,7 @@
   
   Vertex.push_back(0);
     
-  PDTcalculate(*this, F);
+  Calculate<Inverse<BasicBlock*> >(*this, F);
   return false;
 }