Debug Info: revert r222195, r222210 and r222239.

This is no longer needed after David's fix at r222377 + r222485.
rdar://18958417

llvm-svn: 222563
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index bb5161d..bf3bb8a 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -567,8 +567,8 @@
 
   if (getDisplayName().empty())
     return false;
-  // Make sure context @ field 1 is a ScopeRef.
-  if (!fieldIsScopeRef(DbgNode, 1))
+  // Make sure context @ field 1 is an MDNode.
+  if (!fieldIsMDNode(DbgNode, 1))
     return false;
   // Make sure that type @ field 3 is a DITypeRef.
   if (!fieldIsTypeRef(DbgNode, 3))
@@ -1005,7 +1005,7 @@
       for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i) {
         DIGlobalVariable DIG(GVs.getElement(i));
         if (addGlobalVariable(DIG)) {
-          processScope(DIG.getContext().resolve(TypeIdentifierMap));
+          processScope(DIG.getContext());
           processType(DIG.getType().resolve(TypeIdentifierMap));
         }
       }