Move bootseq_tests/bootseq_test from Spring into here

[arhag]

Update as necessary to make it work with Savanna enabled libtester and any further changes needed to reflect changes made to the core contract since this test was written (e.g. changes to how the b1 account is handled.

See original test here: https://github.com/AntelopeIO/spring/blob/2e6bebc4e10ea4f8ecba2a5c021d808262b5661e/unittests/bootseq_tests.cpp

[ericpassmore]

moved to eosnetworkfoundation/eos-system-contracts