[nfc] Fix two leaks where clang::ManglerContext was not cleaned up.

Author: zoecarver

lib/AST/ASTMangler.cpp

@@ -266,8 +266,8 @@ std::string ASTMangler::mangleGlobalVariableFull(const VarDecl *decl) {
       if (clangDecl->getDeclContext()->isTranslationUnit()) {
         Buffer << clangDecl->getName();
       } else {
-        clang::MangleContext *mangler =
-          decl->getClangDecl()->getASTContext().createMangleContext();
+        std::unique_ptr<clang::MangleContext> mangler(
+            decl->getClangDecl()->getASTContext().createMangleContext());
         mangler->mangleName(clangDecl, Buffer);
       }
     }

lib/Sema/CSApply.cpp

@@ -187,8 +187,8 @@ static ValueDecl *generateSpecializedCXXFunctionTemplate(
   // Generate a name for the specialized function.
   std::string newNameStr;
   llvm::raw_string_ostream buffer(newNameStr);
-  clang::MangleContext *mangler =
-      specialized->getASTContext().createMangleContext();
+  std::unique_ptr<clang::MangleContext> mangler(
+      specialized->getASTContext().createMangleContext());
   mangler->mangleName(specialized, buffer);
   buffer.flush();
   // Add all parameters as empty parameters.