[DRAFT] Tests: Use small timeouts for server selection tests in `http.txt`

[amotl]

Dear Sebastian,

this patch is based on the commit 575f6a3c60 you submitted the other day with crate/crate-python#431. I would like to investigate if it might improve timing behaviour/flakyness on CI, as documented at crate/crate-python#404.

With kind regards, Andreas.

[amotl]

crate/crate-python#630 happens on this as well. Sigh.

-- https://github.com/crate/crate-python/actions/runs/3218108206/jobs/5261874131#step:4:381