[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/Hello/Hello.cpp

@@ -12,13 +12,14 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "hello"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/IR/Function.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+#define DEBUG_TYPE "hello"
+
 STATISTIC(HelloCounter, "Counts number of functions greeted");
 
 namespace {