common/f2fs: introduce _require_f2fs_io_command Update existing f2fs testcases to utilize the new _require_f2fs_io_command() helper for verifying required f2fs_io subcommands instead of basic executable checks or open coding. Suggested-by: Zorro Lang <zlang@kernel.org> Signed-off-by: Chao Yu <chao@kernel.org> Reviewed-by: Zorro Lang <zlang@kernel.org> Signed-off-by: Zorro Lang <zlang@kernel.org>