[REVIEW] update subgraph tests and remove legacy pagerank

[Iroy30]

No description provided.

[codecov-io]

Codecov Report

Merging #1378 (3fccf7b) into branch-0.18 (2fb0725) will increase coverage by 0.06%.
The diff coverage is 56.79%.

@@               Coverage Diff               @@
##           branch-0.18    #1378      +/-   ##
===============================================
+ Coverage        60.38%   60.44%   +0.06%     
===============================================
  Files               67       69       +2     
  Lines             3029     3120      +91     
===============================================
+ Hits              1829     1886      +57     
- Misses            1200     1234      +34     

Impacted Files	Coverage Δ
python/cugraph/centrality/__init__.py	100.00% <ø> (ø)
python/cugraph/dask/structure/renumber.py	0.00% <0.00%> (ø)
python/cugraph/link_analysis/pagerank.py	100.00% <ø> (ø)
python/cugraph/comms/comms.py	34.52% <25.00%> (ø)
python/cugraph/dask/common/input_utils.py	23.07% <28.57%> (+1.14%)	⬆️
python/cugraph/utilities/utils.py	66.92% <30.76%> (-4.63%)	⬇️
python/cugraph/dask/common/mg_utils.py	37.50% <38.09%> (-2.50%)	⬇️
python/cugraph/community/spectral_clustering.py	72.54% <38.46%> (-11.67%)	⬇️
python/cugraph/structure/number_map.py	59.20% <50.00%> (+3.24%)	⬆️
python/cugraph/structure/graph.py	66.99% <76.47%> (+0.19%)	⬆️
... and 14 more

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[afender]

Thanks!

[BradReesWork]

@gpucibot merge