pkgsMusl.postgresql: mark v12 and v13 with JIT as broken

Those currently don't build on master, not sure whether they ever built
correctly in the first place.

pkgs/servers/sql/postgresql/generic.nix

@@ -285,7 +285,9 @@ let
       # resulting LLVM IR isn't platform-independent this doesn't give you much.
       # In fact, I tried to test the result in a VM-test, but as soon as JIT was used to optimize
       # a query, postgres would coredump with `Illegal instruction`.
-      broken = jitSupport && (stdenv.hostPlatform != stdenv.buildPlatform);
+      broken = (jitSupport && stdenv.hostPlatform != stdenv.buildPlatform)
+        # Allmost all tests fail FATAL errors for v12 and v13
+        || (jitSupport && stdenv.hostPlatform.isMusl && olderThan "14");
     };
   });