tests(integration): avoid passive health check flakiness

[locao]

Summary

Checklist

• The Pull Request has tests
• There's an entry in the CHANGELOG
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Full changelog

• wait until http test server is unhealthy before continuing the test.
• using some tolerance on the number of requests answered by each proxied test server, we are testing the health check here, not the ring balancer behavior.
• removed some parenthesis from comments to avoid messing up with vim.

[ADD-SP]

LGTM

And I strongly agree with this statement:

using some tolerance on the number of requests answered by each proxied test server, we are testing the health check here, not the ring balancer behavior.

[oowl]

LGTM

[RobSerafini]

@locao Any benefit to cherrypick/backport this change?

[locao]

@RobSerafini yes, this flakiness was in the code since a long time. I will backport this change.

[team-gateway-bot]

The backport to release/3.1.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/3.1.x release/3.1.x
# Navigate to the new working tree
cd .worktrees/backport-release/3.1.x
# Create a new branch
git switch --create backport-10881-to-release/3.1.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 9ceaddbde341e08fb7650d45c8e7f3e301f5dfae
# Push it to GitHub
git push --set-upstream origin backport-10881-to-release/3.1.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.1.x

Then, create a pull request where the base branch is release/3.1.x and the compare/head branch is backport-10881-to-release/3.1.x.

[team-gateway-bot]

The backport to release/3.2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/3.2.x release/3.2.x
# Navigate to the new working tree
cd .worktrees/backport-release/3.2.x
# Create a new branch
git switch --create backport-10881-to-release/3.2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 9ceaddbde341e08fb7650d45c8e7f3e301f5dfae
# Push it to GitHub
git push --set-upstream origin backport-10881-to-release/3.2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.2.x

Then, create a pull request where the base branch is release/3.2.x and the compare/head branch is backport-10881-to-release/3.2.x.