Did IBD on mainet and testnet with `-checkpoints=0 -assumevalid=0`
src/test/checkdatasig_tests.cpp is changed to reflect the new behavior of always allowing op_cds regardless of flag value.
src/test/sigopcount_tests.cpp remains the same to check that the flag still changes sigops counting behavior.
src/test/data/script_tests.json "BAD_OPCODE" test cases removed
src/test/script_test.cpp CHECKDATASIG test cases duplicated with flag off.