[Syntax] Show input code on tests failures. NFC

clang/unittests/Tooling/Syntax/TreeTest.cpp

@@ -515,6 +515,8 @@ void foo() {
   )txt"}};
 
   for (const auto &T : Cases) {
+    SCOPED_TRACE(T.first);
+
     auto *Root = buildTree(T.first);
     std::string Expected = llvm::StringRef(T.second).trim().str();
     std::string Actual = llvm::StringRef(Root->dump(*Arena)).trim();