Flakey memory screen test

[CoderDake]

https://github.com/flutter/devtools/runs/6280344534?check_suite_focus=true

Encountered during #4055

[srawlins]

Closing as stale with insufficient information: The linked CI run logs from 2022 are no longer available and no test name or reproduction details were recorded. In addition, the Memory screen test suite has undergone significant refactoring since this was filed.

If there is more work to do here, please let us know by filing a new issue with up to date information. Thanks!