[reference-binding] Fix pattern dumping.

Author: gottesmm

lib/AST/ASTDumper.cpp

@@ -479,7 +479,10 @@ namespace {
       PrintWithColorRAII(OS, ParenthesisColor) << ')';
     }
     void visitBindingPattern(BindingPattern *P) {
-      printCommon(P, P->isLet() ? "pattern_let" : "pattern_var");
+      SmallString<64> name;
+      name += "pattern_";
+      name += P->getIntroducerStringRef();
+      printCommon(P, name.c_str());
       OS << '\n';
       printRec(P->getSubPattern());
       PrintWithColorRAII(OS, ParenthesisColor) << ')';