WL#3718: provide a way to update bad default values CREATing LIKE

Affects: Server-7.1   —   Status: Un-Assigned   —   Priority: Very High

See BUG#22909, which includes a patch to fix default values when creating one
table from another table.

CREATE LIKE has a shortcut for creation that copies the FRM file, while the
normal method of creating a table has many consistency checks.  We should
generalize a way of checking sanity as the BUG#22909 patch does for one specific
idea.  

Probably pull the normal table-creation checks out into a function that both
CREATE TABLE ... and CREATE LIKE use.