replaced SeqILU0 with SeqILU in ISTL backend

4 jobs for issue/istl_ilu0_precon_deprecated in 26 minutes and 31 seconds (queued for 8 seconds)
Status Job ID Name Coverage
  Test
passed #7020
debian:10 clang-6-libcpp-17

00:26:30

passed #7019
debian:10 gcc-8-17

00:21:11

passed #7021
debian:9 gcc-6-14

00:18:16

passed #7022
ubuntu:18.04 clang-6-17

00:25:31