[Modules] Fix potential ODR violations by sinking the DEBUG_TYPE

definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206844 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/SimplifyCFG.cpp

@@ -11,7 +11,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "simplifycfg"
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/STLExtras.h"
@@ -50,6 +49,8 @@
 using namespace llvm;
 using namespace PatternMatch;
 
+#define DEBUG_TYPE "simplifycfg"
+
 static cl::opt<unsigned>
 PHINodeFoldingThreshold("phi-node-folding-threshold", cl::Hidden, cl::init(1),
    cl::desc("Control the amount of phi node folding to perform (default = 1)"));