[GAE/tests] Add GAE tests for FLASH algorithms of bfs and cc

[longbinlai]

Committed-by: longbinlai from Dev container

Fix issue #2824

[github-actions]

🎊 PR Preview 512f101 has been successfully built and deployed to https://alibaba-graphscope-build-pr-2869.surge.sh

_{🤖 By surge-preview}

[lixueclaire]

You could use ./gs format python to format the code

[lixueclaire]

LGTM～

[codecov-commenter]

Codecov Report

Merging #2869 (fe3fd9a) into main (387f915) will increase coverage by 23.61%.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #2869       +/-   ##
===========================================
+ Coverage   42.59%   66.20%   +23.61%     
===========================================
  Files          99       99               
  Lines       10657    10667       +10     
===========================================
+ Hits         4539     7062     +2523     
+ Misses       6118     3605     -2513     

Impacted Files	Coverage Δ
python/graphscope/tests/unittest/test_flash.py	100.00% <100.00%> (+100.00%)	⬆️

... and 61 files with indirect coverage changes

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