Prow does not wait for all tests to pass before merging following a `/lgtm`

[jljaco]

Consider this example PR from the code-generator repo: aws-controllers-k8s/code-generator#378

In this case, @a-hilaly issued an /lgtm comment before all of the e2e tests had passed, and ack-bot triggered a merge of the PR immediately. The results of the e2e tests were never successfully reported in the PR (as it happens, one or more of them ended up failing).

Steps to reproduce

1. Create a PR in any Prow-managed repo
2. Get an OWNER to issue /lgtm well before e2e tests have completed
3. See that the merge happens immediately, before all tests have completed.

Expected outcome
We expect for Prow to wait until all tests pass before merging the PR.

Environment

Prod Prow cluster

[RedbackThomson]

This is actually a feature. @vijtrip2 Added the service controller tests into the code-generator CI so that we could check there were no errors when using the new generator for a sampling of the controllers. However, sometimes we add new features to the code-generator that we understand will break the code-generator for those controllers. For example, if we make a backward incompatible change to the generator.yaml schema, or we add a new code-generator method stub that does not match the version of the runtime that those controller go.mod files import. Those tests are useful for catching bugs when we don't intend to create backward incompatible changes, but are not blocking so we are able to merge them without requiring a forceful override.