Cleanup check pending

We don't need to pass the db configs to `check_pending_migrations`
because we always want to loop through all of them so the argument
doesn't gain us anything. It's also a private API so applications
shouldn't be consuming this method (and therefore makes it even less
necessary to allow configs to be passed in)

Author: eileencodes

activerecord/lib/active_record/migration.rb

@@ -638,9 +638,7 @@ def check_pending!(connection = Base.connection)
       end
 
       def load_schema_if_pending!
-        all_configs = db_configs_in_current_env
-
-        needs_update = !all_configs.all? do |db_config|
+        needs_update = !db_configs_in_current_env.all? do |db_config|
           Tasks::DatabaseTasks.schema_up_to_date?(db_config, ActiveRecord.schema_format)
         end
 
@@ -653,7 +651,7 @@ def load_schema_if_pending!
           end
         end
 
-        check_pending_migrations(db_configs: all_configs)
+        check_pending_migrations
       end
 
       def maintain_test_schema! # :nodoc:
@@ -679,9 +677,10 @@ def disable_ddl_transaction!
         @disable_ddl_transaction = true
       end
 
-      def check_pending_migrations(db_configs: db_configs_in_current_env) # :nodoc:
+      def check_pending_migrations # :nodoc:
         prev_db_config = Base.connection_db_config
-        db_configs.each do |db_config|
+
+        db_configs_in_current_env.each do |db_config|
           Base.establish_connection(db_config)
           check_pending!
         end