Add a test for calling a non-trivial recursive function.

Author: rniwa

clang/test/Analysis/Checkers/WebKit/uncounted-local-vars.cpp

@@ -302,6 +302,8 @@ struct TreeNode {
   }
 
   int recursiveCost();
+  int recursiveWeight();
+  int weight();
 
   int cost { 0 };
   mutable unsigned refCount { 0 };
@@ -317,4 +319,12 @@ int TreeNode::recursiveCost() {
   return totalCost;
 }
 
+int TreeNode::recursiveWeight() {
+  unsigned totalCost = weight();
+  for (TreeNode* node = firstChild; node; node = node->nextSibling)
+    // expected-warning@-1{{Local variable 'node' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]}}
+    totalCost += recursiveWeight();
+  return totalCost;
+}
+
 } // namespace local_var_in_recursive_function