Cleanup and unify Thrust/CUB test CMake

The CMakeLists.txt files for Thrust and CUB test folders has gotten very complicated over the years. Features have been added, remove, modified, and there's a lot of leftover complexity that's no longer needed.

Additionally, the features provided have diverged -- `%PARAM%` parsing, expected compiler diagnostic checks, target customization methods, etc -- are either missing or handled differently in each.

There's a load of technical debt here to pay off by cleaning these up to remove unneeded complexity, unifying feature sets, and ideally abstracting the complexity out into the CCCL level so we can work towards a uniform test features set across CCCL, rather than reimplementing things like `%PARAM%` parsing and diagnostic checks repeatedly for each subproject.