Add NullStmt::Clone and use it

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71823 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateInstantiateExpr.cpp b/lib/Sema/SemaTemplateInstantiateExpr.cpp
index e747236..50d5d44 100644
--- a/lib/Sema/SemaTemplateInstantiateExpr.cpp
+++ b/lib/Sema/SemaTemplateInstantiateExpr.cpp
@@ -480,7 +480,7 @@
 }
 
 Sema::OwningStmtResult TemplateStmtInstantiator::VisitNullStmt(NullStmt *S) {
-  return SemaRef.Owned(new (SemaRef.Context) NullStmt(S->getSemiLoc()));
+  return SemaRef.Owned(S->Clone(SemaRef.Context));
 }
 
 Sema::OwningStmtResult TemplateStmtInstantiator::VisitLabelStmt(LabelStmt *S) {