pgsql: Use in-place tablespaces in regression test.

Use in-place tablespaces in regression test.

Remove the machinery from pg_regress that manages the testtablespace
directory.  Instead, use "in-place" tablespaces, because they work
correctly when there is a streaming replica running on the same host.

Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKGKpRWQ9SxdxxDmTBCJoR0YnFpMBe7kyzY8SUQk%2BHeskxg%40mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/d6d317dbf6154b3d33fb53e1c3433f039b5d4d74

Modified Files
--------------
src/test/regress/GNUmakefile             |  3 +--
src/test/regress/expected/tablespace.out | 20 ++++++++++++------
src/test/regress/pg_regress.c            | 35 --------------------------------
src/test/regress/sql/tablespace.sql      | 19 +++++++++++------
src/tools/msvc/vcregress.pl              |  2 --
5 files changed, 28 insertions(+), 51 deletions(-)