As of WT-7130, we have a workload that stresses 4.2's lookaside as expected. We should run this workload against 4.4 and tweak this workload to be more or less stressful to show a discrepancy between the two versions.

The first step is to fix the cache target in 4.4 to line up with 4.2. The dirty cache fill ratio seems quite different between 4.2 and 4.4 (20% vs 10% trigger by the look of it). I tried changing eviction_updates_trigger to default to 20 when building master but it didn't seem to make a difference.