Fixes also MDEV-13488: InnoDB writes CRYPT_INFO even though
encryption is not enabled.
Problem was that we created encryption metadata (crypt_data) for
system tablespace even when no encryption was enabled and too early.
System tablespace can be encrypted only using key rotation.
Test innodb-key-rotation-disable, innodb_encryption, innodb_lotoftables
require adjustment because INFORMATION_SCHEMA INNODB_TABLESPACES_ENCRYPTION
contain row only if tablespace really has encryption metadata.
fil_crypt_set_thread_cnt: Send message to background encryption threads
if they exits when they are ready. This is required to find tablespaces
requiring key rotation if no other changes happen.
fil_crypt_find_space_to_rotate: Decrease the amount of time waiting
when nothing happens to better enable key rotation on startup.
fsp_header_init: Write encryption metadata to page 0 only if tablespace is
encrypted or encryption is disabled by table option.
i_s_dict_fill_tablespaces_encryption : Skip tablespaces that do not
contain encryption metadata. This is required to avoid too early
wait condition trigger in encrypted -> unencrypted state transfer.
open_or_create_data_files: Do not create encryption metadata
by default to system tablespace.
