Save test-perf data in csv
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Most data analytics and visualization tools (e.g. Google Data Studio and Amazon Quick Sight) seem to want .csv input, not .json. This PR makes .csv the default data format.
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in testing_commands.py, I linked the new command to test_perf.sh
in test_perf.sh, it would prepare tp5n.zip and virtual environment
then run test_all.sh
