1. Extend the calpontsys.syscolumn system catalog table
with a new column, 'charsetnum'.
'charsetnum' field is set to the 'number' member of the
'charset_info_st' struct defined in the server in m_ctype.h.
For CHAR/VARCHAR/TEXT column types, 'charset_info_st' is
initialized to the charset/collation of the column, which
is set at the column-level or at the table-level in the DDL.
For BLOB/VARBINARY binary column types, 'charset_info_st' is
initialized to my_charset_bin (charsetnum=63).
For all other column types, charsetnum is set to 0.
2. Add support for the newly added 'charsetnum' column in the
automatic system catalog upgrade logic in dbbuilder.
For existing table definitions, charsetnum for the column is
defaulted to 0.
3. Add MTR test case that creates a few table definitions with
a range of charset/collation combinations and queries the
calpontsys.syscolumn system catalog table with the charsetnum
field for the columns in the table DDLs.
