* remove duplicate test file
* move all uuidv7 tests into plugin/type_uuid/mysql-test/type_uuid/
* remove mysys/ changes
* auto my_random_bytes() fallback - removes duplicate code from uuid,
  and fixes all other users of my_random_bytes() that don't check
  the return value (because, perhaps, they don't need crypto-strong
  random bytes)
* End of 11.6 -> 11.7 in tests
* clarify the warning text
* UUID_VERSION_MASK()/UUID_VARIANT_MASK() must not depend on the version
* allow 4x more monotonic uuidv7 per millisecond - instead of stretching
  1000 microseconds over 12 bits, let's use extra 2 bits as a counter