fix cache file judge (#27369)

paddle/fluid/inference/tests/api/CMakeLists.txt

@@ -9,8 +9,8 @@ if(WITH_GPU AND TENSORRT_FOUND)
 endif()
 
 function(download_data install_dir data_file)
-    string(REGEX MATCH "[^/\\]+$" data_file ${data_file})
-    if (NOT EXISTS ${install_dir}/${data_file})
+    string(REGEX MATCH "[^/\\]+$" file_name ${data_file})
+    if (NOT EXISTS ${install_dir}/${file_name})
         inference_download_and_uncompress(${install_dir} ${INFERENCE_URL} ${data_file})
     endif()
 endfunction()