Bug#972246: numba, python3.9, dolfinx

[Rebecca N. Palmer]

Control: affects -1 + pynpoint python-loompy umap-learn
Control: affects -1 + dolfinx python-numpy-groupies

As this bug cannot immediately be fixed, numba may be removed from 
testing to unblock the python3.9 transition (#966426).

(If any of the failed tests are silently wrong answers, please do *not* 
upload a numba version that "fixes" this by ignoring the tests without 
discussion.)

pandas will drop its python3-numba build/autopkgtest-dependency 
(#973589).  Other reverse dependencies that can do so (dolfinx??) should 
do the same if they wish to stay in testing.