Fix missing/incorrect file paths for in-repo addons re-exporting files into the app that are also extended/overridden in the app.

[GCheung55]

Given a repo with an in-repo-addon that re-exports a module, e.g. service, when the repo has an overriding file of what the in-repo-addon exports, then the overriding file should be included in the lcov file.

E.g., Given the following paths exists in the app

app/services/my-service.js
lib/my-in-repo-addon/addon/services/my-service.js
lib/my-in-repo-addon/app/services/my-service.js

Expected: lcov file should include the following lines.

SF:app/services/my-service.js
SF:lib/my-in-repo-addon/addon/services/my-service.js

Actual: lcov file includes the wrong path, such as the following lines.

SF:lib/my-in-repo-addon/app/services/my-service.js
SF:lib/my-in-repo-addon/addon/services/my-service.js

[GCheung55]

I thought of two solutions.

1. Only add the to fileLookup object if the property didn't already exist.
2. Reverse the order of how the paths are included, which gives app/ paths a higher priority than the addon's app/ paths.

I went with solution 2, as it made more sense to control the order instead of modifying how a property is set and follows how addon app/ and app/ paths are merged by ember-cli.

[GCheung55]

test-packages/in-repo-addon-test.js is failing because the snapshot is different. I'm not sure how to update the snapshot and if I should update the snapshot.

[rwjblue]

Thanks for working on this! Only had one small comment, but overall this looks good to me!

[rwjblue]

› 1 snapshot failed from 1 test suite. Inspect your code changes or run yarn test -u to update them.

@GCheung55 - Can you do yarn test -u to update the snapshot with the new coverage data?

[rwjblue]

Thanks!