* Provide backwards compatibility extension to name resolution of
  coalesced columns. The patch allows such columns to be qualified
  with a table (and db) name, as it is in 4.1.
  Based on a patch from Monty.

* Adjusted tests accordingly to test both backwards compatible name
  resolution of qualified columns, and ANSI-style resolution of
  non-qualified columns.
  For this, each affected test has two versions - one with qualified
  columns, and one without. 


mysql-test/include/ps_query.inc:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/bdb.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/innodb.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/join.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/join_nested.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/join_outer.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/null_key.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/order_by.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_2myisam.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_3innodb.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_4heap.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_5merge.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_6bdb.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/ps_7ndb.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/select.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/subselect.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/r/type_ranges.result:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/bdb.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/innodb.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/join.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/join_nested.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/join_outer.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/null_key.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/order_by.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/select.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/subselect.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
mysql-test/t/type_ranges.test:
  Put back old tests to test that coalesced columns of natural joins can be qualified.
sql/sql_base.cc:
  * Applied Monty's patch for backwards compatible name resolution
    of qualified columns. The idea is:
    - When a column is qualified, search for the column in all
      tables/views underlying each natural join. In this case
      natural joins are *not* considered leaves.
    - If a column is not qualified, then consider natural joins
      as leaves, thus directly search the result columns of
      natural joins.
  * Simplified 'find_field_in_tables()' - unified two similar
    loops into one.
sql/table.cc:
  - Removed method & members not needed after Monty's patch.
sql/table.h:
  - Removed method & members not needed after Monty's patch.
tests/mysql_client_test.c:
  Put back old tests to test that coalesced columns of natural joins can be qualified.