Partly revert a9880321 and 9ae19ed5.

Also, higher cost for [elim_modal_bupd_fupd], so that it is not taken in place of [elim_modal_fupd_fupd] in spec patterns.
1 job for master in 10 minutes and 40 seconds
Status Job ID Name Coverage
  Test
passed #1563
coq
buildjob

00:10:40