postgresql: drop obsolete musl checkPhase fix

pkgs/servers/sql/postgresql/generic.nix

···
     # autodetection doesn't seem to able to find this, but it's there.
     checkTarget = "check";
 
-    # TODO: Remove after the next set of minor releases on May 9th 2024
-    preCheck =
-      # On musl, comment skip the following tests, because they break due to
-      #     ! ERROR:  could not load library "/build/postgresql-11.5/tmp_install/nix/store/...-postgresql-11.5-lib/lib/libpqwalreceiver.so": Error loading shared library libpq.so.5: No such file or directory (needed by /build/postgresql-11.5/tmp_install/nix/store/...-postgresql-11.5-lib/lib/libpqwalreceiver.so)
-      # See also here:
-      #     https://git.alpinelinux.org/aports/tree/main/postgresql/disable-broken-tests.patch?id=6d7d32c12e073a57a9e5946e55f4c1fbb68bd442
-      if stdenv'.hostPlatform.isMusl then ''
-        substituteInPlace src/test/regress/parallel_schedule \
-          --replace "subscription" "" \
-          --replace "object_address" ""
-      '' else null;
-
     disallowedReferences = [ stdenv'.cc ];
 
     passthru = let