In the tokenizer we will now recognize the character set names
of MariaDB and return a specific token for those. However, where
a character set name is not expected, it will automatically be
treated as an identifier.
Note that when the character set name is explicitly specified
for a literal string, the name must be prefixed with an underscore.
That is, if the character set name is "latin1", when used when
specifying a literal string, it's used as "_latin1 'a'".
Note that this does not fix the sqlite3 bug causing a leak, but
since the statement will now correctly be parsed, the leak will
not manifest itself.