test: add null judge to avoid NullPointerException but why?

Author: wind4869

src/main/java/org/tron/core/config/args/Storage.java

@@ -141,11 +141,15 @@ public void deleteAllStoragePaths() {
     }
 
     for (Property property : propertyMap.values()) {
-      String path = property.getPath();
-      if (path != null) {
-        FileUtil.recursiveDelete(path);
+      // TODO: NullPointerException in CI, but normal in local
+      if (property != null) {
+        String path = property.getPath();
+        if (path != null) {
+          FileUtil.recursiveDelete(path);
+        }
       }
     }
+
   }
 
   private boolean hasProperty(String dbName) {