Do not pad VARBINARY or BINARY columns. (Bug #14189)
innodb.test, innodb.result: Add test cases for foreign key constraints
between VARBINARY and BINARY columns, and between VARCHAR BINARY and
CHAR BINARY columns.
innobase_init(): Assert that
DATA_MYSQL_BINARY_CHARSET_COLL == my_charset_bin.number.
dtype_get_pad_char(): Do not pad VARBINARY or BINARY columns.
row_ins_cascade_calc_update_vec(): Refuse ON UPDATE CASCADE
when trying to change the length of a VARBINARY column
that refers to or is referenced by a BINARY column. BINARY
columns are no longer padded on comparison, and thus they
cannot be padded on storage either.
Mostly fix bug #13778, when FOREIGN_KEY_CHECKS=0 we still need to check
that datatypes between foreign key references are compatible.
Add test cases (also for bug #9802).