test/nginx: prevent request() from normalising paths

[alxndrsn]

This will be useful for testing nginx config at some point, and very misleading if trying to test path normalisation differences and request() collapses path traversals.

What has been done to verify that this works as intended?

• existing tests pass
• checked with new tests relating to collapsed path-traversal

Why is this the best possible solution? Were any other approaches considered?

While not immediately used, this will be useful for testing nginx config at some point, and very misleading if trying to test path normalisation differences and request() collapses path traversals.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

No effect.

Does this change require updates to documentation? If so, please file an issue here and include the link below.

No.

Before submitting this PR, please make sure you have:

• branched off and targeted the next branch OR only changed documentation/infrastructure (master is stable and used in production)
• verified that any code or assets from external sources are properly credited in comments or that everything is internally sourced