postgresql: run full test-suite during checkPhase

doCheck was enabled in #61395 which does not mention an explicit decision
for "check" instead of "check-world". The latter runs more tests, for example
for contrib modules etc. - but results in higher build times..

Running "nix-build -A postgresql":
- with doCheck = false: 46s
- with checkTarget = "check": 60s
- with checkTarget = "check-world": 75s

pkgs/servers/sql/postgresql/generic.nix

@@ -250,7 +250,7 @@ let
 
     doCheck = !stdenv'.hostPlatform.isDarwin;
     # autodetection doesn't seem to able to find this, but it's there.
-    checkTarget = "check";
+    checkTarget = "check-world";
 
     passthru = let
       this = self.callPackage generic args;