cmSystemTools: Re-order extract_tar logic

Simplify extraction message logic to be easier to follow and to write a
newline before any error messages that may be produced.  Also flip
handling of the archive_write_header return code to handle success in
the "then" case and failure in the "else" case.
cmake: Avoid '-E tar' failure to extract symlinks on Windows (#13251)

If a symlink fails to extract and the host system is Windows then report
a warning and skip the entry instead of failing.  This will allow
archives containing symbolic links to be extracted on Windows with
somewhat gracefully degraded behavior.
Merge topic 'archive-skip-symlink-on-windows' into next

4c383b5 cmake: Avoid '-E tar' failure to extract symlinks on Windows (#13251)
0d8552c cmSystemTools: Re-order extract_tar logic