pgsql: Remove PostgreSQL::Test::Utils::perl2host completely

Remove PostgreSQL::Test::Utils::perl2host completely

Commit f1ac4a74de disabled this processing, and as nothing has broken (as
expected) here we proceed to remove the routine and adjust all the call
sites.

Backpatch to release 10

Discussion: https://postgr.es/m/0ba775a2-8aa0-0d56-d780-69427cf6f33d@dunslane.net
Discussion: https://postgr.es/m/20220125023609.5ohu3nslxgoygihl@alap3.anarazel.de

Branch
------
REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/b4a6ceed52eef851083a8681d85fc92c33be75b1

Modified Files
--------------
src/test/perl/PostgresNode.pm                    |  4 +--
src/test/perl/TestLib.pm                         | 33 ------------------------
src/test/recovery/t/014_unlogged_reinit.pl       |  4 +--
src/test/recovery/t/017_shm.pl                   |  2 +-
src/test/recovery/t/025_stuck_on_old_timeline.pl |  2 +-
5 files changed, 5 insertions(+), 40 deletions(-)