When MySQL 5.7.9 was merged to MariaDB 10.2.2, an important
debug assertion was omitted from mlog_write_initial_log_record_low().

mlog_write_initial_log_record_low(): Put back the assertion
mtr_t::is_named_space().

fil_crypt_start_encrypting_space(), fil_crypt_rotate_page():
Call mtr_t::set_named_space() before modifying any pages.

fsp_flags_try_adjust(): Call mtr_t::set_named_space(). This additional
breakage was introduced in the merge of MDEV-11623 from 10.1. It was
not caught because of the missing debug assertion in
mlog_write_initial_log_record_low().

Remove some suppressions from the encryption.innodb-redo-badkey test.