Remove unused testing helper: generate_test_samples()

[IndrajeetPatil]

No description provided.

[github-actions]

This is how benchmark results would change (along with a 95% confidence interval in relative change) if 4f78252 is merged into main:

• ✔️cache_applying: 152ms -> 155ms [-3.81%, +6.79%]
• ✔️cache_recording: 547ms -> 542ms [-5.51%, +3.92%]
• ✔️without_cache: 943ms -> 939ms [-0.73%, +0.03%]

Further explanation regarding interpretation and methodology can be found in the documentation.

[lorenzwalthert]

Hmmmm... Not sure we actually want to remove these functions. I think Kirill deliberately committed these generators, not sure maybe he thought we'd later change them later to re-generate tests. Hasn't happened though... I guess we can remove them, and come back here in case we need them.