Update win_logger.cc : assert failed when return value not checked. (-DROCKSDB_ASSERT_STATUS_CHECKED) (#7955)

Summary:
Ignore return value on WinLogger::CloseInternal() when build with -DROCKSDB_ASSERT_STATUS_CHECKED on windows.

It's a good way to ignore check here?

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7955

Reviewed By: jay-zhuang

Differential Revision: D26524145

Pulled By: ajkr

fbshipit-source-id: f2f643e94cde9772617c68b658fb529fffebd8ce