CI binary tests taking long time on dev

[daljit46]

Recent CI runs, that some binary tests take a long time to execute. Three tests in particular: dwi2fod_msmt_default, dwi2fod_msmt_masked and dwi2tensor_dkt_constrained.
Example:

 42/396 Test  #42: dwi2fod_msmt_default ....................................   Passed  121.10 sec
        Start  43: dwi2fod_msmt_masked
 43/396 Test  #43: dwi2fod_msmt_masked .....................................   Passed  107.94 sec
        Start  44: dwi2tensor_bzero
 44/396 Test  #44: dwi2tensor_bzero ........................................   Passed    0.02 sec
        Start  45: dwi2tensor_default
 45/396 Test  #45: dwi2tensor_default ......................................   Passed    0.02 sec
        Start  46: dwi2tensor_dkt_constrained
 46/396 Test  #46: dwi2tensor_dkt_constrained ..............................   Passed  174.18 sec

I hadn't noticed this earlier, but I believe this is due to some change that happened in the last few months. We should investigate whether this can be rectified.

[daljit46]

Using git bisect I have tracked down the root cause to be #3182, specifically bcbc2e4.

[bjeurissen]

I can confirm this:

Before bcbc2e4 in constrained_least_squares.h:

❯ hyperfine -r 1 'dwi2fod msmt_csd dwi.mif csf.txt true_csf.mif gm.txt true_gm.mif wm.txt true_wm.mif -lmax 0,0,8 -mask mask.mif -force'
Benchmark 1: dwi2fod msmt_csd dwi.mif csf.txt true_csf.mif gm.txt true_gm.mif wm.txt true_wm.mif -lmax 0,0,8 -mask mask.mif -force
Time (abs ≡): 26.263 s [User: 402.494 s, System: 1.011 s]

After bcbc2e4 in constrained_least_squares.h:

❯ hyperfine -r 1 'dwi2fod msmt_csd dwi.mif csf.txt true_csf.mif gm.txt true_gm.mif wm.txt true_wm.mif -lmax 0,0,8 -mask mask.mif -force'
Benchmark 1: dwi2fod msmt_csd dwi.mif csf.txt true_csf.mif gm.txt true_gm.mif wm.txt true_wm.mif -lmax 0,0,8 -mask mask.mif -force
Time (abs ≡): 665.921 s [User: 9831.902 s, System: 80.548 s]

[daljit46]

Closed by #3261.