pg_regress cleans up tablespace twice.

Hello.

I saw a failure of vcregress check with the following message several
times, on a machine under a heavy load and maybe with realtime virus
scanning.

> pg_regress: could not create directory ".../testtablespace": Permission denied.

I found that pg_regress repeats the sequence
rmtree(tablespace)->make_directory(tablespace) twice under
initialize_environment. So it should be THE DELETE_PENDING. It is
because the code is in convert_sourcefiles_in, which is called
succssively twice in convert_sourcefiles.

But in the first place it comes from [1] and the comment says:

> * XXX it would be better if pg_regress.c had nothing at all to do with
> * testtablespace, and this were handled by a .BAT file or similar on
> * Windows.  See pgsql-hackers discussion of 2008-01-18.

Is there any reason not to do that in vcregress.pl?  I think the
commands other than 'check' don't needs this.

[1] https://www.postgresql.org/message-id/11718.1200684807%40sss.pgh.pa.us

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center