OP_BSWAP has been added to enums, assigned the number 0xbc. T707
This doesn't change the behavior in any way (except for how OP_BSWAP will be displayed), so adding tests seems unwarranted. Also, there already is a bswap_tests.cpp. I suggest renaming that file to byteswap_tests.cpp to allow OP_BSWAP to have a test file that's easier recognizable.