Split eosio.system_tests.cpp so tests can run in parallel in CICD to reduce overall CICD time

[linh2931]

Currently eosio.system_tests.cpp is 5,921 lines long and takes 5 minutes to run in CICD libtester (https://github.com/AntelopeIO/spring/actions/runs/9468157289/job/26085190747#step:16:984). The next longest test is eosio_system_finalizer_key_unit_test which is about 1 minute. We can split eosio.system_tests.cpp into multiple files (tests) and make each of them run around 1 minute; those tests can run in parallel with other tests. This will reduce libtester running time to about 1 minute, a huge saving without risks, plus smaller files to reduce compilation time if changes are in one small file.

[heifner]

In addition many of these test produce a large number of blocks for no reason. See changes in AntelopeIO/spring#273
For example:
https://github.com/AntelopeIO/spring/pull/273/files#diff-772ea8af1ac7513dba7209d87abdd10757824ab895a16b9f174f740c17232508L35