Fixed bug #12144.
Added an optimization that avoids key access with null keys for the 'ref'
method when used in outer joins. The regilar optimization with adding
IS NOT NULL expressions is not applied for outer join on expressions as
the predicates of these expressions are not pushed down in 4.1.
null_key.result, null_key.test:
Added a test case for bug #12144.
Fixed (together with Guilhem) bugs in mysqlbinlog regarding --offset
Prefix addresses with 0x for easier comparisons of debug logs
Fixed problem where MySQL choosed index-read even if there would be a much better range on the same index
This fix changed some 'index' queries to 'range' queries in the test suite
Don't create 'dummy' WHERE clause for trivial WHERE clauses where we can remove the WHERE clause.
This fix removed of a lot of 'Using where' notes in the test suite.
Give NOTE instead of WARNING if table/function doesn't exists when using DROP IF EXISTS
Give NOTE instead of WARNING for safe field-type conversions
