pgsql: Revert commits 290acac92b and 8a7e9e9dad.

Revert commits 290acac92b and 8a7e9e9dad.

This commit revert the commits to add a test case that tests the 'force'
option when there is an active backend connected to the database being
dropped.

This feature internally sends SIGTERM to all the backends connected to the
database being dropped and then the same is reported to the client. We
found that on Windows, the client end of the socket is not able to read
the data once we close the socket in the server which leads to loss of
error message which is not what we expect. We also observed similar
behavior in other cases like pg_terminate_backend(),
pg_ctl kill TERM <pid>. There are probably a few others like that. The
fix for this requires further study.

Discussion: https://postgr.es/m/E1iaD8h-0004us-K9@gemulon.postgresql.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/98a9b37ba70f24b28478360d9cf7f190b0f75f8d

Modified Files
--------------
src/bin/scripts/t/050_dropdb.pl | 8 ++-
src/bin/scripts/t/051_dropdb_force.pl | 104 -------------------------------
src/test/perl/TestLib.pm | 37 -----------
src/test/recovery/t/013_crash_restart.pl | 63 ++++++++++++-------
4 files changed, 47 insertions(+), 165 deletions(-)