Can't install on Ubuntu with OCaml 4.14.0 + opam

Description: Ubuntu 20.04.5 LTS

```
opam install expect_test_helpers_kernel --debug
00:00.002 GSTATE LOAD-GLOBAL-STATE @ /home/olle/.opam
00:00.002 RSTATE LOAD-REPOSITORY-STATE @ /home/olle/.opam
00:00.097 RSTATE Loaded /home/olle/.opam/repo/state.cache in 0.094s
00:00.291 RSTATE Cache found
00:00.291 STATE LOAD-SWITCH-STATE @ 4.14.0
00:00.405 STATE Detected changed packages (marked for reinstall): {}
00:00.409 STATE Switch state loaded in 0.118s
00:00.409 FILE(switch-state) Wrote /home/olle/.opam/4.14.0/.opam-switch/backup/state-20221002183022.export in 0.000s
00:00.631 CLIENT INSTALL expect_test_helpers_kernel
00:01.119 SYSTEM [log-1224189-4bcc67] (in 0.048s) lsb_release -s -r
00:01.148 SYSTEM [log-1224189-ccabea] (in 0.019s) ocamlc -vnum
00:01.459 CLIENT Orphans: (changes: { expect_test_helpers_kernel.v0.9.0, expect_test_helpers_kernel.v0.10.0, expect_test_helpers_kernel.v0.11.0, expect_test_helpers_kernel.v0
.12.0, expect_test_helpers_kernel.v0.13.0 }, transitive: false) -> full {}, versions {}
00:02.135 SOLVER resolve request=install:(expect_test_helpers_kernel) remove:() upgrade:()
00:04.234 SOLVER Load cudf universe (depopts:false, build:true, post:true)
00:04.562 CUDF resolve request=install:(expect%5ftest%5fhelpers%5fkernel) remove:() upgrade:()
00:04.562 SOLVER Calling solver builtin-mccs+glpk with criteria -removed,-count[version-lag,request],-count[version-lag,changed],-changed
00:06.743 CUDF Solver call done in 2.182
00:08.694 CLIENT conflict!
Sorry, no solution found: there seems to be a problem with your request.

No solution found, exiting
00:08.694 SYSTEM rm /home/olle/.opam/4.14.0/.opam-switch/backup/state-20221002183022.export

Reproduce the reported `opam install expect_test_helpers_kernel --debug` command on Ubuntu 20.04.5 with OCaml 4.14.0, then investigate why the solver reports no solution; the issue is resolved when the package installation succeeds or the incompatibility is clearly identified.

Written by the indexing model from the issue text.