postgresql.withPackages: expose tests passthru

This allows running tests for example on `orioledb`, which is not only a
`postgresql` package, but wrapped with an extension.

pkgs/servers/sql/postgresql/wrapper.nix

@@ -64,6 +64,11 @@ buildEnv (finalAttrs: {
       };
     };
 
+    tests = lib.mapAttrs (
+      _: test:
+      if test.passthru or { } ? "override" then test.passthru.override finalAttrs.finalPackage else test
+    ) postgresql.tests;
+
     withJIT = recurse (_: installedExtensions ++ [ postgresql.jit ]);
     withoutJIT = recurse (_: lib.remove postgresql.jit installedExtensions);