Let printf do the formatting instead aligning strings ourselves.

While at it, merge some format strings.

llvm-svn: 142140
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d9d0d27..632b614 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6592,7 +6592,7 @@
     return;
 
   // Dump the current SDNode, but don't end the line yet.
-  OS << std::string(indent, ' ');
+  OS.indent(indent);
   N->printr(OS, G);
 
   // Having printed this SDNode, walk the children: