of two query plans with identical costs.

- Unify EXPLAIN printout for <subqueryN> tables with regular tables
- Update test results for <subqueryN> tables:
  s/unique_key/distinct_key/g
  s/1.0/100.0/ for "filtered" column

- Fix test failures: do not use make_cond_after_sjm()'s result in case
  of merged SJ-Materialization lookup
- Update test results

MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Address feedback
- Code cleanup (not finished)

- Make join buffering take into account that join_tabs are not a 
  single linear array anymore
- Remove outer join + SJ-Materialization crash (OJ+SJ the processing
  is most likely still incorrect)

- Make join buffering code to take into account that JOIN_TABs are not a 
  linear array anymore.

- First code, needs cleanup.

MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Change "SUBQUERY#n" to "<subquery{n}>" in EXPLAIN output. We need to it to be
  lowercase so that EXPLAIN results do not differ in case between systems with
  case-sensitive and case-insensitive filesystems.
- Remove garbage comments, add better comments.

MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Remove JOIN::all_tables as it is not useful.
- Better wording in comments

MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Code cleanu.
- Make MWL#90 code require @@optimizer_switch='semijoin=on'
- Update test results with the above
- Fork subselect_mat.test - we want to check both semi-join materialization, 
  which now has broader scope and non-semijoin materialization.

MWL#90: Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Merge into 5.3-subqueries

Subqueries: Inside-out execution for non-semijoin materialized subqueries that are AND-parts of the WHERE
- Code cleanup
- Query plan change is due to s/ha_rows JOIN_TAB::read_time/double JOIN_TAB::read_time/

- Better comments

- Better comments
- Use more appropriate return types for functions
- Provide handling where it was missing.

correct number of tables (when we're optimizing a materializable semi-join 
nest, we're considering only tables from within that nest).

- for Item-based materialization, it was "materialized subselect"
- for SJ-Materialization it was "subquery%d"

semi-join, where the the REF buffer format was mistaken to be in
record format instead of key format. The error was that the null
byte for all fields of the record was in the front of the buffer,
and not before each field data.

  subqueries that are AND-parts of the WHERE
- Make test results handle same-cost QEP races

  subqueries that are AND-parts of the WHERE
- Update test results

  subqueries that are AND-parts of the WHERE
- Update test results (checked, we get 0 because the subquery is actually
  evaluated by the EXPLAIN).

  non-semijoin materialized subqueries that are AND-parts of the WHERE
- Update test results.

was not cleaned up between PS re-executions. The reason was two-fold:
- a merge with mysql-6.0 missed select_union::cleanup() that should
  have cleaned up the temp table, and
- the subclass of select_union used by materialization didn't call
  the base class cleanup() method.

  subqueries that are AND-parts of the WHERE
- First code (needs cleanup).

Fixed an error where the priority queue for the indexes used for partial
matching was not emptied after each execution in all cases.

invoke proper Item_int constructor.

- Add Item_in_subselect::get_identifier() that returns subquery's id
- Change select_describe() to produce output in new format
- Update test results (checked)

of which satisfied the ORDER BY clause).

mysql-test/r/union.result:
  Update test results (checked, it should be "DEPENDENT SUBQUERY" as it will actually run subquery's join multiple times. There is no reason to do that but executor will still do it)