When mongoreplay was written it was done somewhat separately from the rest of the tools codebase. As a result, it ended up with its own evergreen configuration file, (.evergreen.yml). This config file is separate from the repo's general config file (common.yml).
Much of the code from evergreen.yml is duplicated code from common anyway. The code that isn't duplicated should be merged into common.yml and .evergreen.yml should be eliminated