Removing not used fixtures from ActionPack test suite

[thiagopradi]

Motivation / Background

This Pull Request has been created because I was looking at the ActionPack test suite and found a few fixture files that are not used anymore.

Checklist

Before submitting the PR make sure the following are checked:

• [ X ] This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• [ N/A ] Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• [ N/A ] Tests are added or updated if you fix a bug or add a feature.
• [ N/A ] CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.