Fix T4267 performance regression
In 54250f2d T4267 regressed a lot (allocs increased from 40k to 100k). This ticket tracks this.
Note that @sgraf812 marked it as "expected to fail" but the new baseline (100k) has been stored (accepted) anyway... This led to "unexpected pass" testsuite failures for any following patch. !2984 (merged) makes T4267 expected to pass again but we probably shouldn't be storing metrics for "expected to fail" tests.