In WT-8208, we added a new debug configuration release_evict_page in session, which evicts pages as they are released. A Python test was written to go along with this change, and we expected cache usage when using the config to be significantly less than the cache usage without the config. However, we found that this was not always the case.

In this failure, the Python test failed the assertion self.assertGreater(prev_cache_usage, cache_usage * 2), and we can see that the values of prev_cache_usage and cache_usage are actually the same.
https://evergreen.mongodb.com/task/wiredtiger_macos_1014_cmake_unit_test_edf2f353acfa275030d51482633436f2f4fa3174_21_11_15_05_31_06

The scope of the ticket is to investigate why this is occurring, and either fix the test or change the way we are evicting pages.