Bugfix1: Set innodb_locks.lock_index to NOT NULL.
If a column in INFORMATION_SCHEMA table has the flag
MY_I_S_MAYBE_NULL and it is not explicitly marked as NOT NULL
with the method ::set_notnull() then it is always rendered as
NULL by MySQL.
Bugfix2: Avoid crashes if lock_index is NULL. It is NULL for table
level locks.
Pointyhat to: Marko
innodb_information_schema.test. Add tests that display most columns from
INFORMATION_SCHEMA.INNODB_LOCKS. Test that quoting of table names works
and respects SQL_MODE='ANSI_QUOTES'.
innobase_print_identifier(): Remove.
innobase_convert_identifier(): New function,
based on innobase_print_identifier().
innobase_convert_name(): New function, similar to ut_print_namel(), but
using a memory buffer.
ut_print_namel(): Use innobase_convert_name().
fill_innodb_locks_from_cache(): Convert lock_table and lock_index by
calling innobase_convert_name().
Add innodb_locks.lock_data column and some relevant tests.
For record locks this column represents the ordering fields of the
locked row in a human readable, SQL-valid, format.
Approved by: Marko
