[TableGen] Change a couple methods to return an ArrayRef instead of a const std::vector reference. NFC

llvm-svn: 241430
diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index 6e982bf..c9a31b6 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -1648,7 +1648,7 @@
   }
 
   OS << " {";
-  const std::vector<Record*> &SC = R.getSuperClasses();
+  ArrayRef<Record *> SC = R.getSuperClasses();
   if (!SC.empty()) {
     OS << "\t//";
     for (const Record *Super : SC)