WIP: Example for a compilation-required-to-fail test

assigned to @kucher

@jfahl_01 Can't see the attempts to build compile_fail under "build-samples" job category...

It works by invoking the compiler (through cmake and make|ninja) at test time ("test-*" jobs), not at compile time. It's happening inside

$ ctest -j$(nproc) -LE '^cuda-debug-(known-failure|slow)$' --output-on-failure
Test project /builds/HPC2SE-Project/pacxx-samples/bsamples
[...]
      Start  6: compile_fail
[...]
 1/36 Test  #6: compile_fail .....................   Passed    0.62 sec

for instance in this job: https://zivgitlab.uni-muenster.de/HPC2SE-Project/pacxx-samples/-/jobs/13326