Remove dependency on ProblemStatBase from ProblemInstatBase

4 jobs for issue/problem_instat_base in 49 minutes and 26 seconds (queued for 13 minutes and 47 seconds)
Status Job ID Name Coverage
  Test
passed #8198
debian:10 clang-6-libcpp-17

00:31:30

passed #8197
debian:10 gcc-8-17

00:21:01

passed #8199
debian:9 gcc-6-14

00:19:10

passed #8200
ubuntu:18.04 clang-6-17

00:28:21