Dependent images are cached and not re-built when their base image's Dockerfile is changed

[lbussell]

See dotnet/dotnet-docker#6110 (comment)

Steps to reproduce the issue

Queue a PR validation build of dotnet-docker repo where some runtime deps Dockerfiles are changed but not any dependent runtime or aspnet Dockerfiles.

Expected behavior

All images dependent on the changed runtime-deps images will be re-built.

Actual behavior

No images dependent on the changed runtime-deps images are re-built. This results in test failures when there is an expected behavior change like in dotnet/dotnet-docker#6110.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[mthalman]

This is a regression that was caused by #1427. That change explicitly prevented it from accounting for locally built base images which is problematic for this scenario.