Moved some old test and added a new test to only be run with mysql-test-run --big

Fixed warnings by valgrind for sum_distinct.test
Enable buffered-record-reads after filesort for InnoDB tables with short primary key
Enabled sort-with-data for MyISAM temporary files


BitKeeper/etc/ignore:
  added tools/mysqltestmanager
client/mysqltest.c:
  Ensure that BIG_TEST is always set to 0 or 1
  Fix the 'eval' also honors 'require'
mysql-test/mysql-test-run.sh:
  Enlarge InnoDB table space for --big tests
mysql-test/r/heap.result:
  Fix after adding more optimzation for filsort
mysql-test/r/sum_distinct.result:
  Move 'slow' part of test to sum_distinct-big.test
mysql-test/t/heap.test:
  Ensure that results are indpendent of optimizer
mysql-test/t/sum_distinct.test:
  Move 'slow' part of test to sum_distinct-big.test
sql/filesort.cc:
  Use 'sort with data' also on temporary files and with INSERT ... SELECT
sql/ha_innodb.h:
  Remove HA_FAST_KEY_READ to enable buffered-record-reads after filesort
sql/handler.h:
  More comments
sql/mysql_priv.h:
  A bit smaller limit for cache for buffered-records-read (after testing)
sql/records.cc:
  Don't use buffered-record-reads if ref_length > MAX_REFLENGTH
  Fixed warning from valgrind in 'sum_distinct'
sql/sql_select.cc:
  Ensure that tempory tables has query_id set for all fields
  (Required for sort-with-data to work on temp files)

mysql-test/r/heap.result

@@ -436,30 +436,30 @@ f	10
 g	10
 h	10
 i	10
-select sql_big_result v,count(t) from t1 group by v limit 10;
-v	count(t)
+select sql_big_result trim(v),count(t) from t1 group by v limit 10;
+trim(v)	count(t)
 a
	1
-a 	10
-b     	10
-c    	10
-d   	10
-e  	10
-f     	10
-g    	10
+a	10
+b	10
+c	10
+d	10
+e	10
+f	10
+g	10
 h	10
-i     	10
-select sql_big_result v,count(c) from t1 group by v limit 10;
-v	count(c)
+i	10
+select sql_big_result trim(v),count(c) from t1 group by v limit 10;
+trim(v)	count(c)
 a
	1
-a 	10
-b     	10
-c    	10
-d   	10
-e  	10
-f     	10
-g    	10
+a	10
+b	10
+c	10
+d	10
+e	10
+f	10
+g	10
 h	10
-i     	10
+i	10
 select c,count(*) from t1 group by c limit 10;
 c	count(*)
 a
	1
@@ -520,18 +520,18 @@ f	10
 g	10
 h	10
 i	10
-select sql_big_result t,count(t) from t1 group by t limit 10;
-t	count(t)
+select sql_big_result trim(t),count(t) from t1 group by t limit 10;
+trim(t)	count(t)
 a
	1
-a 	10
-b     	10
-c    	10
-d   	10
-e  	10
-f     	10
-g    	10
+a	10
+b	10
+c	10
+d	10
+e	10
+f	10
+g	10
 h	10
-i     	10
+i	10
 drop table t1;
 create table t1 (a char(10), unique (a));
 insert into t1 values ('a');