cache test: loosen conditions on cache usage

This fixes config_tests on aarch64 macOS. The key difference is that they use 16k pages, so LMDB space usage also behaves a bit different.

added easyfix label

Build verified only non-interactively, at https://logs.nix.ci/?key=nixos/nixpkgs.188194&attempt_id=c455f87f-a262-4bb1-af27-9ab0d87ac4ef

added 1 commit

• c098925d - NEWS: mention config_tests for macOS

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merged

mentioned in commit a8472be3