The fle2_compact.js test asserts the size of the ESC collection to be a certain value after doing a compaction operation. If the read operation that counts the number of ESC documents reads from a secondary that has not replicated the ESC deletes, it could return a higher than expected count. We should add the assumes_read_preference_unchanged tag so that this test gets excluded on suites that override the runCommand to attach a $readPreference other than primary to commands.