Fix priorities of IntoLaterN instances.

This should fix iris-examples.
6 jobs for master in 10 minutes and 5 seconds (queued for 1 second)
Status Name Job ID Coverage
  Build
passed build-coq.8.6.1 #7458
fp-timing

00:03:14

passed build-coq.8.7.1 #7457
fp-timing

00:03:02

 
  Deploy
passed opam #7459

00:00:14

passed reverse-deps #7460

00:00:14

 
  Build More
passed build-coq.8.7.0 #7462
fp-timing

00:03:07

passed build-coq.8.7.dev #7461
fp-timing

00:03:25