pgsql: Make PostgreSQL::Test::Cluster::init_from_backup handle tablespa

Make PostgreSQL::Test::Cluster::init_from_backup handle tablespaces.

This commit doesn't use this infrastructure for anything new, although
it does adapt 010_pg_basebackup.pl to use it. However, a future commit
will use this to improve test coverage for pg_combinebackup.

Patch by me, reviewed (but not fully endorsed) by Andres Freund.

Discussion: http://postgr.es/m/CA+TgmoYdXTjo9iQeoipTccDpWZzvBNS6EndY2uARM+T4yG_yDg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/6bf5c42b5546984df29289918f952e6211069c54

Modified Files
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src/bin/pg_basebackup/t/010_pg_basebackup.pl | 21 ++-----
src/test/perl/PostgreSQL/Test/Cluster.pm     | 93 +++++++++++++++++++++++++---
2 files changed, 90 insertions(+), 24 deletions(-)