Concurrent use of portals and simple queries invalidates portals

To reproduce:

//from CursorTest.scala 
  sessionTest("invalidation") { s =>
    cursor(s).use { c =>
      for {
        _ <- c.fetch(1)
        _ <- s.execute(sql"select 1;".query(int4))
        _ <- c.fetch(1)
      } yield ()
    }
  }

This will fail with exception Problem: Portal "portal_2" does not exist.

From what is seen on tcpdump and wireshark, Portal get invalidated implicitly and server takes it as a given and not sends any message for its invalidation.

expected behavior:
This is hard to say, as it is exactly what postgres do which is inconvenient IMO, but this is issue can be mitigated by warnings on document, method docs etc.

Start with the invalidation test in CursorTest.scala and run the sessionTest("invalidation") reproduction. Trace the interaction between c.fetch(1) and s.execute(sql"select 1;".query(int4)); done should prevent the portal_2 failure or clearly document the portal invalidation behavior and its mitigation.