The tests now rely on --verbose to print out useful information in the
logs that can be used for debugging purposes. In case of a failure in
some of the tests an overall cleanup is not done, this is particularly
useful for PGDATA which could still be used for extra failure analysis.
Performance of compression is quite questionable on many objects like
that and makes the routines aimed at managing file copy, backup and restore
more complicated than they should be.
This commit results in a largely simplified code in data.c, which will
be helpful when integrating differential backup using WAL file lookup.
This new facility has the advantage on not relying on static data when
generating the tests making the whole facility more robust. This is
basically taken from the upstream project pg_rman and adapted for the
sake of this pet project, so most of the credit go to Kyotaro Horiguchi
and Amit Langote regarding this facility. However I have adapted a bunch
of things and fixed a lot of redundancy and code duplication.
