fix: use values that are representable as double in test

This should fix a test failure on i386:

lrutest: ./dune/common/test/lrutest.cc:29: void lru_test(): Assertion `lru.front() == 1.3 && lru.back() == 2.0' failed.

assigned to @ansgar

enabled an automatic merge when the pipeline for cb09f854 succeeds

merged

mentioned in commit ca3f2b27

picked the changes into the branch cherry-pick-ca3f2b27 with commit 5a7466e0

mentioned in commit 5a7466e0

mentioned in merge request !1330 (merged)