ldas-tools-framecpp 3.0.4 fails tests on Debian Bullseye, Ubuntu Focal and Jammy (MR)

Although there's a mechanism (FIXTURES_{SETUP,REQUIRES}) implemented to run test_downconvert_* only after the correesponding setup_downconvert_* steps, this fails for Debian and Ubuntu, except Debian Bookworm. (To prove, run grep 'Test #' ldas-tools-framecpp_*.log.)

The reason for this in unclear, it may be related to the version of CMake in use (3.18.4 for Bullseye and Focal, 3.22.1 for Jammy, 3.25.1 for Bookworm).

Since using a higher version of CMake isn't easily possible, fixing the testing order against the overall --parallel option (which, on this build machine, results in -j32 for make) requires using --no-parallel for the dh_auto_test action.

A MR will be provided.