Alter TokuDB table comment should not using copying algorithm and

rebuild whole engine data, only FRM definition should be changed.

Make `ha_tokudb::check_if_supported_inplace_alter()` return

`HA_ALTER_INPLACE_EXCLUSIVE_LOCK` while altering comment, and mysql

server will invoke `ha_tokudb::inplace_alter_table` which will do

nothing for altering comment.

Besides table comment, there are many other create options that

should be ignored by TokuDB, and they are all handled in this patch.

Btw, this patch has been pushed to TokuDB upstream.

This patch also contains a postfix for bug#88847, which handles

cases when UK or Key with auto-inc fileld is invisible.