Fix EXPERIMENTAL_LOUVAIN_TEST on Pascal

[ChuckHastings]

experimental::louvain uses a coco::static_map which is not supported on Pascal and earlier GPUs.

The first attempt at implementing checks for Pascal attempted to exclusively use preprocessor directives to control building the executable and deciding whether to run it or not. However, nvcc uses the preprocessor to create different files to be compiled for host, and each combination of devices being compiled. Exclusively using preprocessor directives created a library that didn't have all of the host and device code necessary to run.

This PR adds a runtime check to raise an exception if running on Pascal, but it will still compile all of the necessary host and device code for other architectures.

[codecov-io]

Codecov Report

Merging #1312 (2316f03) into branch-0.18 (70d9abd) will not change coverage.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           branch-0.18    #1312   +/-   ##
============================================
  Coverage        60.38%   60.38%           
============================================
  Files               67       67           
  Lines             3029     3029           
============================================
  Hits              1829     1829           
  Misses            1200     1200           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 70d9abd...2316f03. Read the comment docs.

[ChuckHastings]

rerun tests