[C++] Remove needless out argument from arrow::internal::InvertBitmap

[asfimport]

arrow::internal::InvertBitmap is defined in bitmap_ops.h

but there seems to be a small mistake in the impl bimap_ops.cc [2] (more like a type IMO)

[1] https://github.com/apache/arrow/blob/master/cpp/src/arrow/util/bitmap_ops.h#L81

[2] https://github.com/apache/arrow/blob/master/cpp/src/arrow/util/bitmap_ops.cc#L392

Reporter: Niranda Perera / @nirandaperera
Assignee: Niranda Perera / @nirandaperera

PRs and other links:

• GitHub Pull Request #10391

_{Note: This issue was originally created as ARROW-12864. Please see the migration documentation for further details.}

[asfimport]

Kouhei Sutou / @kou:
Issue resolved by pull request 10391
#10391